SAT Math : x and y Intercept

Study concepts, example questions & explanations for SAT Math

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Example Questions

Example Question #6 : How To Find X Or Y Intercept

A line has the equation: 2x+4y=8. 

What is the x-intercept?

Possible Answers:

4

-4

8

-8

0

Correct answer:

4

Explanation:

To find the x-intercept, rearrange the equation 2x+4y=8 so that x is isolated:

2x=-4y+8

x=-2y+4

Using the point-slope formula, we see that the x-intercept is 4.

Example Question #7 : How To Find X Or Y Intercept

What is the y intercept of the following function of x? 

y = 3x 

Possible Answers:

3

–3

0

1

–1

Correct answer:

0

Explanation:

The answer is 0 because in slope intercept form, y = mx + b; b is the y intercept. In this case b = 0. 

Example Question #8 : How To Find X Or Y Intercept

What is the x-intercept of a line with a slope of 5 and y-intercept of 3.5?

Possible Answers:

(–0.7, 0)

(3.5, 0)

(0.7, 0)

(–3.5, 0)

(0, –0.7)

Correct answer:

(–0.7, 0)

Explanation:

To solve this, first find the equation of our line.  The form of the question gives it to us very directly.  We can use the slope-intercept form (y = mx + b).

y = 5x + 3.5

The x-intercept is found by setting y = 0, because that will give us the x-value at which the line crosses the x-axis.

0 = 5x + 3.5; –3.5 = 5x; x = –3.5 / 5 or –0.7.  The point will be (–0.7, 0)

Example Question #9 : How To Find X Or Y Intercept

Determine the y-intercept of the following line:

\dpi{100} \small 3x+6y=9

Possible Answers:

\dpi{100} \small 1.5

\dpi{100} \small 9

\dpi{100} \small \frac{1}{3}

\dpi{100} \small 3

\dpi{100} \small 6

Correct answer:

\dpi{100} \small 1.5

Explanation:

The y-intercept occurs when \dpi{100} \small x=0

\dpi{100} \small 3x+6y=9

\dpi{100} \small 3(0)+6y=9

\dpi{100} \small 0+6y=9

\dpi{100} \small y = \frac{9}{6}=1.5

Example Question #10 : How To Find X Or Y Intercept

At what point does the graph 3y-2x=31 cross the -axis?

Possible Answers:

Correct answer:

Explanation:

The graph crosses the -axis where x=0. So plugging in and solving yields \frac{31}{3}

Example Question #11 : How To Find X Or Y Intercept

Find the x-intercepts of  25x^{2}+4y^{2} = 9.

Possible Answers:

\pm 5

\frac{3}{5}

5

2

\pm \frac{3}{5}

Correct answer:

\pm \frac{3}{5}

Explanation:

To find the x-intercepts, plug y=0 into the equation and solve for x.

25x^{2} + 4\cdot 0^{2} = 9

25x^{2} = 9

x^{2} = \frac{9}{25}

x = \pm \frac{3}{5}

Don't forget that there are two solutions, both negative and positive!

Example Question #12 : How To Find X Or Y Intercept

A line with the exquation y=x^2+3x+c passes through the point .  What is the -intercept?

Possible Answers:

Correct answer:

Explanation:

By plugging in the coordinate, we can figure out that .  The -Intercept is when , plugging in 0 for gives us .

Example Question #13 : How To Find X Or Y Intercept

What are the -intercept(s) of the following line:

Possible Answers:

Correct answer:

Explanation:

We can factor and set  equal to zero to determine the -intercepts.

satisfies this equation.

 

Therefore our -intercepts are  and .

Example Question #171 : Geometry

Which of the following lines does not intersect the line ?

Possible Answers:

Correct answer:

Explanation:

Parallel lines never intersect, so you are looking for a line that has the same slope as the one given. The slope of the given line is –4, and the slope of the line in y = –4x + 5 is –4 as well. Since these two lines have equal slopes, they will run parallel and can never intersect.

Example Question #172 : Geometry

Find the y-intercept of .

Possible Answers:

3

14

12

5

7

Correct answer:

7

Explanation:

To find the y-intercept, set x equal to zero and solve for y.

This gives y = 3(0)2 + 2(0) +7 = 7.

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