Graphing Functions - PSAT Math

  1. What does the vertical line test determine for a graph in the coordinate plane?
    Whether the graph represents a function. Functions have at most one y-value per x-value.
  2. Identify the domain of the rational function y=1x−ay=\frac{1}{x-a} for constant aa.
    All real xx except x≠ax\ne a. Division by zero is undefined, excluding x=ax=a from the domain.
  3. What is the range of a function ff as shown on its graph?
    All yy-values of points on the graph. The vertical extent of the graph shows all possible outputs.
  4. What is the effect on the graph of replacing f(x)f(x) with −f(x)-f(x)?
    Reflect across the xx-axis. Negating outputs flips all yy-values to opposite signs.
  5. Identify the slope and yy-intercept of y=−3x+5y=-3x+5.
    Slope −3-3; yy-intercept (0,5)(0,5). Read directly from y=mx+by=mx+b form: m=−3m=-3, b=5b=5.
  6. Identify the transformation: y=f(−x)y=f(-x) compared to y=f(x)y=f(x).
    Reflection across the yy-axis. Negative input flips all points horizontally across the yy-axis.
  7. What is the yy-intercept of the line y=−2x+7y=-2x+7?
    (0,7)(0,7). Substitute x=0x=0: y=−2(0)+7=7y=-2(0)+7=7.
  8. Identify the transformation: y=af(x)y=af(x) for a>1a>1 compared to y=f(x)y=f(x).
    Vertical stretch by factor aa. Multiplying output by a>1a>1 stretches graph vertically.
  9. What is the definition of the yy-intercept of a graph of y=f(x)y=f(x)?
    The point where x=0x=0, so y=f(0)y=f(0). The yy-intercept occurs where the graph crosses the yy-axis.
  10. Identify the domain and range of the parent function y=xy=\sqrt{x}.
    Domain: x≥0x\ge 0; Range: y≥0y\ge 0. Square root requires non-negative input and produces non-negative output.
  11. What is the vertical line test used to determine when a graph represents yy as a function of xx?
    No vertical line intersects the graph more than once. Functions have only one yy-value per xx-value.
  12. What transformation occurs to y=f(x)y=f(x) when graphing y=f(x)+ky=f(x)+k for constant kk?
    Vertical shift by kk units (up if k>0k>0, down if k<0k<0). Adding kk to outputs shifts the entire graph vertically.
  13. What transformation does y=−f(x)y=-f(x) represent on the graph of y=f(x)y=f(x)?
    Reflection across the xx-axis. Negating the output flips all yy-values across the xx-axis.
  14. What transformation occurs to y=f(x)y=f(x) when graphing y=f(x−h)y=f(x-h) for constant hh?
    Horizontal shift by hh units (right if h>0h>0, left if h<0h<0). Subtracting hh from inputs shifts the graph horizontally.
  15. What is the axis of symmetry of y=a(x−h)2+ky=a(x-h)^2+k?
    The vertical line x=hx=h. Parabolas are symmetric about the vertical line through the vertex.
  16. What is the axis of symmetry for y=a(x−h)2+ky=a(x-h)^2+k?
    x=hx=h. Vertical line through vertex where parabola folds.
  17. What is the vertical line test for deciding whether a graph represents a function?
    A graph is a function if every vertical line hits it at most once. Functions have only one yy-value per xx-value.
  18. For y=a(x−h)2+ky=a(x-h)^2+k, what is the axis of symmetry?
    Axis of symmetry is x=hx=h. The parabola is symmetric about the vertical line through vertex.
  19. What transformation occurs to y=f(x)y=f(x) when graphing y=f(−x)y=f(-x)?
    Reflection across the yy-axis. Negating inputs flips the graph left-to-right.
  20. What is the slope between points (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2) on a graph?
    y2−y1x2−x1\frac{y_2-y_1}{x_2-x_1}. Slope equals rise over run: change in yy divided by change in xx.
  21. What are the vertical and horizontal asymptotes of y=1x−ay=\frac{1}{x-a}?
    Vertical: x=ax=a; Horizontal: y=0y=0. The function approaches these lines but never reaches them.
  22. What is the yy-intercept of the line given by y=mx+by=mx+b?
    The point (0,b)(0,b). When x=0x=0, y=m(0)+b=by=m(0)+b=b, giving the point (0,b)(0,b).
  23. What is the definition of an xx-intercept of a function y=f(x)y=f(x) on its graph?
    A point where y=0y=0, so it satisfies f(x)=0f(x)=0. The xx-intercept occurs where the graph crosses the xx-axis.
  24. What does it mean on a graph if (a,b)(a,b) lies on y=f(x)y=f(x)?
    f(a)=bf(a)=b. The point satisfies the function equation.
  25. Find the yy-intercept of f(x)=2x2−3x+4f(x)=2x^2-3x+4.
    (0,4)(0,4). Substitute x=0x=0: f(0)=2(0)2−3(0)+4=4f(0)=2(0)^2-3(0)+4=4.
  26. What is the definition of an xx-intercept (zero) of y=f(x)y=f(x)?
    Any xx where f(x)=0f(x)=0, giving a point (x,0)(x,0). Zeros occur where the graph crosses the xx-axis.
  27. What is the axis of symmetry of the parabola y=a(x−h)2+ky=a(x-h)^2+k?
    The vertical line x=hx=h. Parabolas are symmetric about the vertical line through vertex.
  28. Identify the end behavior of y=x2y=x^2 as x→±∞x\to\pm\infty.
    y→∞y\to\infty as x→∞x\to\infty and as x→−∞x\to-\infty. The parabola opens upward, so both ends go to infinity.
  29. What is the range of a function given its graph?
    All yy-values attained by points on the graph. The range includes all yy-coordinates that appear on the graph.
  30. What is the definition of the xx-intercept of a graph of y=f(x)y=f(x)?
    A point where y=0y=0, so f(x)=0f(x)=0. The xx-intercept occurs where the graph crosses the xx-axis.
  31. Identify the vertex of y=(x−4)2−7y=(x-4)^2-7.
    (4,−7)(4,-7). In vertex form y=a(x−h)2+ky=a(x-h)^2+k, vertex is (h,k)(h,k).
  32. What does it mean for a relation to be a function in terms of xx-values and outputs?
    Each xx-value corresponds to exactly one output yy. This is the definition of a function - no two outputs for one input.
  33. What is the yy-intercept of y=f(x)y=f(x) in terms of ff?
    The point (0,f(0))(0, f(0)). Occurs where the graph crosses the yy-axis, when x=0x=0.
  34. What is the definition of the yy-intercept of a function y=f(x)y=f(x) on its graph?
    The point where x=0x=0, so the intercept is (0,f(0))(0,f(0)). The yy-intercept occurs where the graph crosses the yy-axis.
  35. What is the slope-intercept form of a linear function and what does each parameter represent?
    y=mx+by=mx+b; slope mm, yy-intercept bb. Linear graphs have constant slope mm and cross yy-axis at (0,b)(0,b).
  36. What is the xx-intercept of y=x−7y=x-7?
    (7,0)(7,0). Set y=0y=0: 0=x−70=x-7 gives x=7x=7, so the intercept is (7,0)(7,0).
  37. Identify the vertical asymptote of f(x)=3x+5f(x)=\frac{3}{x+5}.
    x=−5x=-5. The function approaches infinity when the denominator x+5=0x+5=0.
  38. What is the effect on the graph of replacing f(x)f(x) with af(x)a f(x) for a>1a>1?
    Vertical stretch by factor aa. Multiplying outputs by a>1a>1 stretches graph away from xx-axis.
  39. Identify the axis of symmetry of y=−2(x+3)2+1y=-2(x+3)^2+1.
    x=−3x=-3. Axis passes through vertex; here h=−3h=-3 gives x=−3x=-3.
  40. What is the definition of the yy-intercept of a function's graph?
    The point where x=0x=0, so y=f(0)y=f(0). The yy-intercept occurs where the graph crosses the yy-axis.
  41. Identify the transformation: y=f(x−k)y=f(x-k) compared to y=f(x)y=f(x).
    Horizontal shift right kk units. Subtracting kk from input shifts graph right (opposite direction).
  42. What is the effect on the graph of y=−f(x)y=-f(x)?
    Reflection across the xx-axis. Negating outputs flips the graph over the xx-axis.
  43. What is the effect on the graph of y=f(x)+ky=f(x)+k for a constant kk?
    Vertical shift up kk units. Adding kk to outputs moves the graph up kk units.
  44. Identify the vertex of the parabola y=(x−3)2−5y=(x-3)^2-5.
    (3,−5)(3,-5). In vertex form, (h,k)=(3,−5)(h,k)=(3,-5) directly.
  45. Identify the transformation: y=−f(x)y=-f(x) compared to y=f(x)y=f(x).
    Reflection across the xx-axis. Negative sign flips all yy-values across the xx-axis.
  46. Find the xx-intercept of y=2x−8y=2x-8 as a point on the coordinate plane.
    (4,0)(4,0). Set y=0y=0: 0=2x−80=2x-8, so x=4x=4.
  47. What transformation does y=af(x)y=af(x) represent for a>1a>1 compared to y=f(x)y=f(x)?
    Vertical stretch by factor aa. Multiplying output by a>1a>1 stretches the graph vertically.
  48. What is the meaning of the range of a function y=f(x)y=f(x) from its graph?
    All yy-values attained by points on the graph. Range is the set of possible output values.
  49. What does the vertical line test determine for a graph in the xyxy-plane?
    Whether the graph represents a function of xx. If any vertical line crosses more than once, it's not a function.
  50. What is the vertical line test used to determine about a graph?
    Whether the graph represents a function of xx. A function has at most one yy-value for each xx-value.
  51. What is the location of the vertex of y=(x−3)2−5y=(x-3)^2-5?
    (3,−5)(3,-5). In vertex form (x−h)2+k(x-h)^2+k, the vertex is at (h,k)(h,k).
  52. What is the effect on the graph of replacing f(x)f(x) with f(x)+kf(x)+k?
    Shift up kk units. Adding kk to outputs increases all yy-values by kk.
  53. What are the xx-intercepts of y=f(x)y=f(x) in terms of an equation involving ff?
    Solutions to f(x)=0f(x)=0, written as points (x,0)(x,0). These are where the graph crosses the xx-axis.
  54. What is the effect on the graph of replacing f(x)f(x) with f(x−h)f(x-h)?
    Shift right hh units. Replacing xx with x−hx-h delays the function by hh units.
  55. What is the effect on the graph of replacing f(x)f(x) with f(ax)f(ax) for a>1a>1?
    Horizontal compression by factor aa. Multiplying inputs by a>1a>1 squeezes horizontally.
  56. What is the vertex of y=a(x−h)2+ky=a(x-h)^2+k?
    Vertex is (h,k)(h,k). The parabola's turning point is at these coordinates.
  57. What is the slope of a line passing through (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2)?
    m=y2−y1x2−x1m=\frac{y_2-y_1}{x_2-x_1}. This formula gives the rate of change between two points.
  58. What is the effect on the graph of replacing f(x)f(x) with af(x)af(x) for a>1a>1?
    Vertical stretch by factor aa. Multiplying outputs by a>1a>1 stretches vertically.
  59. What is the effect on the graph of y=f(x)y=f(x) when graphing y=f(−x)y=f(-x)?
    Reflect across the yy-axis. Replacing xx with −x-x flips all points horizontally.
  60. Identify the yy-intercept of f(x)=3x−5f(x)=3x-5.
    (0,−5)(0,-5). Substitute x=0x=0: f(0)=3(0)−5=−5f(0)=3(0)-5=-5.
  61. What transformation does y=f(−x)y=f(-x) represent on the graph of y=f(x)y=f(x)?
    Reflection across the yy-axis. Negating the input flips all xx-values across the yy-axis.
  62. Identify the vertex form of a quadratic and state its vertex in terms of hh and kk.
    y=a(x−h)2+ky=a(x-h)^2+k; vertex is (h,k)(h,k). This form directly shows the parabola's turning point.
  63. What is the meaning of aa in y=a(x−h)2+ky=a(x-h)^2+k for the parabola's opening?
    a>0a>0 opens up; a<0a<0 opens down. Sign of aa determines if parabola opens upward or downward.
  64. What transformation does y=f(x)+ky=f(x)+k represent on the graph of y=f(x)y=f(x)?
    A vertical shift up kk units (down if k<0k<0). Adding kk to the output shifts every point up by kk units.
  65. Identify the transformation in y=−f(x)y=-f(x) relative to y=f(x)y=f(x).
    Reflection across the xx-axis. Negative sign flips all y-values across the x-axis.
  66. What are the xx-intercepts of y=(x−1)(x+4)y=(x-1)(x+4)?
    (−4,0)(-4,0) and (1,0)(1,0). Set y=0y=0 and solve: (x−1)(x+4)=0(x-1)(x+4)=0 gives x=1x=1 or x=−4x=-4.
  67. What does it mean for a function to be increasing on an interval?
    As xx increases, f(x)f(x) increases on that interval. The graph rises from left to right.
  68. Identify the axis of symmetry of y=−2(x+1)2+7y=-2(x+1)^2+7.
    Axis of symmetry is x=−1x=-1. In vertex form, h=−1h=-1 so axis of symmetry is x=−1x=-1.
  69. Identify the yy-intercept of y=3x−4y=3x-4.
    yy-intercept is (0,−4)(0,-4). Substitute x=0x=0: y=3(0)−4=−4y=3(0)-4=-4.
  70. Identify the vertex of y=(x−4)2+7y=(x-4)^2+7.
    (4,7)(4,7). In vertex form (x−h)2+k(x-h)^2+k, vertex is (h,k)(h,k).
  71. Identify the xx-intercept of y=2x+6y=2x+6.
    xx-intercept is (−3,0)(-3,0). Set y=0y=0 and solve: 0=2x+60=2x+6, so x=−3x=-3.
  72. Identify the domain of f(x)=1x−2f(x)=\frac{1}{x-2}.
    All real xx with x≠2x\ne 2. The function is undefined when the denominator equals zero at x=2x=2.
  73. What is the effect on the graph of replacing f(x)f(x) with f(x+h)f(x+h)?
    Shift left hh units. Replacing xx with x+hx+h advances the function by hh units.
  74. Identify the yy-intercept of the line y=−3x+7y=-3x+7 as an ordered pair.
    (0,7)(0,7). When x=0x=0, y=−3(0)+7=7y=-3(0)+7=7.
  75. For y=a(x−h)2+ky=a(x-h)^2+k, what are the vertex coordinates?
    Vertex is (h,k)(h,k). The parabola's turning point is shifted to (h,k)(h,k) from origin.
  76. Find the slope of the line passing through (2,5)(2,5) and (6,1)(6,1).
    m=−1m=-1. Using slope formula: 1−56−2=−44=−1\frac{1-5}{6-2}=\frac{-4}{4}=-1.
  77. What is the domain of a function ff as shown on its graph?
    All xx-values of points on the graph. The horizontal extent of the graph shows all possible inputs.
  78. What is the domain of f(x)=x−5f(x)=\sqrt{x-5}?
    x≥5x\ge 5. Square roots require non-negative inputs: x−5≥0x-5\ge 0.
  79. What transformation does y=f(ax)y=f(ax) represent for a>1a>1 compared to y=f(x)y=f(x)?
    Horizontal compression by factor aa (scale factor 1a\frac{1}{a}). Multiplying input by a>1a>1 compresses the graph horizontally.
  80. What is the domain of a function given its graph?
    All xx-values for which the graph has at least one point. The domain includes all xx-coordinates that appear on the graph.
  81. What is the effect on the graph of y=f(x)y=f(x) when graphing y=f(x)+ky=f(x)+k?
    Shift up kk units (down if k<0k<0). Adding kk to the output shifts the entire graph vertically.
  82. What is the slope of the line given by y=mx+by=mx+b?
    Slope is mm. In slope-intercept form, the coefficient of xx is the slope.
  83. What is the domain of a function in a graphing context?
    All xx-values for which f(x)f(x) is defined. The horizontal extent of the graph.
  84. What is the definition of the yy-intercept of a function y=f(x)y=f(x) on its graph?
    The point where x=0x=0, which is (0,f(0))(0,f(0)). The y-intercept occurs when the input variable equals zero.
  85. What is the effect on the graph of y=f(x)y=f(x) when graphing y=af(x)y=af(x) for a>1a>1?
    Vertical stretch by factor aa. Multiplying output by a>1a>1 stretches graph away from xx-axis.
  86. What is the effect on the graph of y=f(x−k)y=f(x-k) for a constant kk?
    Horizontal shift right kk units. Subtracting kk from inputs shifts right kk units.
  87. What is the vertex form of a parabola, and what point is the vertex?
    y=a(x−h)2+ky=a(x-h)^2+k with vertex (h,k)(h,k). This form makes the vertex coordinates immediately visible.
  88. What is the effect on the graph of y=f(ax)y=f(ax) when a>1a>1?
    Horizontal compression by factor aa. Multiplying inputs by a>1a>1 compresses horizontally.
  89. What is the slope-intercept form of a line, and what do mm and bb represent?
    y=mx+by=mx+b; mm is slope and bb is the yy-intercept. Standard form showing slope and where line crosses yy-axis.
  90. What is the slope-intercept form of a line, and what do its parameters represent?
    y=mx+by=mx+b; mm is slope and bb is the yy-intercept. This form directly shows how the line rises and where it crosses the yy-axis.
  91. What is the slope of the line given by y=mx+by=mx+b?
    Slope is mm. In slope-intercept form, the coefficient of xx is the slope.
  92. What is the effect on the graph of y=af(x)y=af(x) when a>1a>1?
    Vertical stretch by factor aa. Multiplying outputs by a>1a>1 stretches vertically.
  93. Identify the vertex of y=(x−3)2−5y=(x-3)^2-5.
    Vertex is (3,−5)(3,-5). Compare to y=a(x−h)2+ky=a(x-h)^2+k to identify h=3h=3 and k=−5k=-5.
  94. What is the effect on the graph of replacing f(x)f(x) with f(x)−kf(x)-k?
    Shift down kk units. Subtracting kk from outputs decreases all yy-values by kk.
  95. Identify the transformation in y=f(−x)y=f(-x) relative to y=f(x)y=f(x).
    Reflection across the yy-axis. Negating input flips all x-values across the y-axis.
  96. Identify the vertex of y=(x−3)2+5y=(x-3)^2+5.
    (3,5)(3,5). Vertex form y=(x−h)2+ky=(x-h)^2+k has vertex at (h,k)(h,k).
  97. What is the yy-intercept of y=f(x)y=f(x) in terms of function notation (when it exists)?
    The point (0,f(0))(0,f(0)). Found by substituting x=0x=0 into the function.
  98. What is the definition of the graph of a function y=f(x)y=f(x) in the coordinate plane?
    The set of all points (x,f(x))(x,f(x)) for allowed xx. Each input xx maps to exactly one output point (x,f(x))(x,f(x)).
  99. Find the slope of the line through (2,1)(2,1) and (6,9)(6,9).
    m=2m=2. Using slope formula: m=9−16−2=84=2m=\frac{9-1}{6-2}=\frac{8}{4}=2.
  100. What is the effect on the graph of replacing f(x)f(x) with f(x−k)f(x-k)?
    Horizontal shift right kk units. Subtracting kk from inputs shifts the graph right.
  101. What transformation does y=f(x−k)y=f(x-k) represent on the graph of y=f(x)y=f(x)?
    A horizontal shift right kk units (left if k<0k<0). Subtracting kk from input shifts the graph right (opposite direction).
  102. What is the slope of a line through points (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2)?
    m=y2−y1x2−x1m=\frac{y_2-y_1}{x_2-x_1}. Rise over run: change in yy divided by change in xx.
  103. Identify the transformation in y=f(x−k)y=f(x-k) relative to y=f(x)y=f(x).
    Horizontal shift right kk units. Subtracting kk from input shifts graph to the right.
  104. Find the xx-intercept of y=2x−8y=2x-8 as an ordered pair.
    (4,0)(4,0). Set y=0y=0: 0=2x−80=2x-8, so x=4x=4.
  105. Identify the slope of the line y=mx+by=mx+b in terms of mm.
    Slope =m=m. In slope-intercept form y=mx+by=mx+b, the coefficient mm is the slope.
  106. What is the definition of the xx-intercept(s) of a function y=f(x)y=f(x) on its graph?
    Point(s) where y=0y=0, so f(x)=0f(x)=0. X-intercepts are where the graph crosses the x-axis.
  107. What are the xx-intercepts of y=f(x)y=f(x) in terms of solutions to an equation?
    Points where f(x)=0f(x)=0, that is, (x,0)(x,0) for solutions of f(x)=0f(x)=0. The graph crosses the xx-axis where the function equals zero.
  108. What is the yy-intercept of y=f(x)y=f(x) in terms of f(0)f(0) (when defined)?
    The yy-intercept is (0,f(0))(0,f(0)). The yy-intercept occurs when x=0x=0, giving the point (0,f(0))(0,f(0)).
  109. What is the range of a function in a graphing context?
    All possible output values y=f(x)y=f(x). The vertical extent of the graph.
  110. What is the definition of the graph of a function ff in the coordinate plane?
    The set of points (x,f(x))(x, f(x)) for all xx in the domain. Each input xx pairs with output f(x)f(x) to form coordinate pairs.
  111. What is the vertex form of a quadratic, and what is its vertex?
    y=a(x−h)2+ky=a(x-h)^2+k; vertex is (h,k)(h,k). Shows parabola's turning point directly.
  112. Identify the xx-intercept of f(x)=2x+6f(x)=2x+6.
    (−3,0)(-3,0). Set f(x)=0f(x)=0: 2x+6=02x+6=0 gives x=−3x=-3.
  113. What is the equation of a line with slope mm and yy-intercept bb?
    y=mx+by=mx+b. Standard form where mm is slope and bb is yy-intercept.
  114. What is the axis of symmetry for y=a(x−h)2+ky=a(x-h)^2+k?
    The vertical line x=hx=h. The parabola is symmetric about this vertical line through the vertex.
  115. What transformation occurs to y=f(x)y=f(x) when graphing y=−f(x)y=-f(x)?
    Reflection across the xx-axis. Negating outputs flips all yy-values to opposite signs.
  116. What is the slope between points (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2)?
    m=y2−y1x2−x1m=\frac{y_2-y_1}{x_2-x_1}. Rise over run formula calculates the rate of change.
  117. What is the effect on the graph of y=f(x)y=f(x) when graphing y=−f(x)y=-f(x)?
    Reflect across the xx-axis. Multiplying output by −1-1 flips all yy-values to opposite sign.
  118. Identify the transformation in y=f(x)+ky=f(x)+k relative to y=f(x)y=f(x).
    Vertical shift up kk units. Adding kk to the output shifts the graph upward.
  119. What does the sign of aa tell you for y=a(x−h)2+ky=a(x-h)^2+k?
    If a>0a>0 it opens up; if a<0a<0 it opens down. The sign determines whether the parabola opens upward or downward.
  120. Identify the domain and range of the parent function y=x2y=x^2.
    Domain: all real xx; Range: y≥0y\ge 0. The parabola extends infinitely left/right but only upward from vertex.
  121. What is the effect on the graph of replacing f(x)f(x) with f(−x)f(-x)?
    Reflect across the yy-axis. Negating inputs reverses the graph horizontally.
  122. What is the slope between two points (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2)?
    m=y2−y1x2−x1m=\frac{y_2-y_1}{x_2-x_1}. Rise over run formula calculates the rate of change.
  123. What is the vertex form of a quadratic and what point does it reveal immediately?
    y=a(x−h)2+ky=a(x-h)^2+k; vertex (h,k)(h,k). The parabola's turning point is at (h,k)(h,k).
  124. Identify the xx-intercepts of y=f(x)y=f(x) using an equation involving f(x)f(x).
    xx-intercepts occur where f(x)=0f(x)=0. These are the points where the graph crosses the xx-axis.
  125. What is the meaning of the domain of a function y=f(x)y=f(x) from its graph?
    All xx-values for which the graph has points. Domain is the set of possible input values.
  126. What is the axis of symmetry of y=ax2+bx+cy=ax^2+bx+c?
    Axis of symmetry is x=−b2ax=-\frac{b}{2a}. Formula finds the x-coordinate of the vertex.
  127. What is the effect on the graph of y=f(x)y=f(x) when graphing y=f(x−h)y=f(x-h)?
    Shift right hh units (left if h<0h<0). Subtracting hh from input shifts graph horizontally (opposite direction).
  128. What is the vertical line test for deciding whether a graph represents a function y=f(x)y=f(x)?
    It is a function if no vertical line intersects the graph more than once. Functions have only one output per input, so vertical lines hit once max.
  129. What is the effect on the graph of y=f(−x)y=f(-x)?
    Reflection across the yy-axis. Negating inputs flips the graph over the yy-axis.
  130. What does it mean for a function to be decreasing on an interval?
    As xx increases, f(x)f(x) decreases on that interval. The graph falls from left to right.
  131. Identify the horizontal asymptote of f(x)=4x−1f(x)=\frac{4}{x-1}.
    y=0y=0. As xx approaches pminftypminfty, the fraction approaches zero.
  132. What is the effect on the graph of y=f(x)y=f(x) when graphing y=f(ax)y=f(ax) for a>1a>1?
    Horizontal compression by factor aa. Multiplying input by a>1a>1 squeezes graph toward yy-axis.
  133. Identify the slope and yy-intercept of the line y=−3x+5y=-3x+5.
    Slope m=−3m=-3 and yy-intercept (0,5)(0,5). Read directly from slope-intercept form: coefficient of xx and constant term.
  134. What does it mean (graphically) if a point (a,b)(a,b) lies on y=f(x)y=f(x)?
    It means f(a)=bf(a)=b. The point satisfies the function equation with x=ax=a and y=by=b.
  135. What is the slope formula between points (x1,y1)(x_1,y_1) and (x2,y2)(x_2,y_2)?
    m=y2−y1x2−x1m=\frac{y_2-y_1}{x_2-x_1}. Rise over run between two points gives the slope.
  136. What are the xx-intercepts of y=f(x)y=f(x) in terms of an equation you solve?
    Solutions to f(x)=0f(x)=0 (points (x,0)(x,0)). Where the graph crosses the xx-axis, so y=0y=0.
  137. What is the vertex form of a quadratic function used for graphing?
    y=a(x−h)2+ky=a(x-h)^2+k. Shows the parabola's vertex at (h,k)(h,k) directly.
  138. Identify the axis of symmetry of y=−2(x+3)2+1y=-2(x+3)^2+1.
    x=−3x=-3. For (x−h)2(x-h)^2 form, axis is x=hx=h; here h=−3h=-3.
  139. Identify the transformation: y=f(ax)y=f(ax) for a>1a>1 compared to y=f(x)y=f(x).
    Horizontal compression by factor aa. Multiplying input by a>1a>1 compresses graph horizontally.
  140. What is the effect on the graph of replacing f(x)f(x) with f(bx)f(bx) for b>1b>1?
    Horizontal compression by factor bb. Multiplying inputs by b>1b>1 squeezes graph toward yy-axis.
  141. What is the point-slope form of a line through (x1,y1)(x_1,y_1) with slope mm?
    y−y1=m(x−x1)y-y_1=m(x-x_1). This form uses a known point and the line's slope.
  142. Identify the transformation: y=f(x)+ky=f(x)+k compared to y=f(x)y=f(x).
    Vertical shift up kk units. Adding kk to the output shifts the entire graph up by kk units.
  143. Identify the yy-intercept of y=f(x)y=f(x) in terms of function notation.
    yy-intercept is (0,f(0))(0,f(0)). Substitute x=0x=0 into the function to find where graph crosses yy-axis.
  144. Identify the slope of the line through (2,1)(2,1) and (6,9)(6,9).
    m=2m=2. Apply slope formula: 9−16−2=84=2\frac{9-1}{6-2}=\frac{8}{4}=2.

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