# SAT Math : x and y Intercept

## 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?

4

-4

8

-8

0

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

3

–3

0

1

–1

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?

(–0.7, 0)

(3.5, 0)

(0.7, 0)

(–3.5, 0)

(0, –0.7)

(–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:

Explanation:

The y-intercept occurs when

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

At what point does the graph  cross the -axis?

Explanation:

The graph crosses the -axis where . So plugging in and solving yields

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

Find the x-intercepts of  .

Explanation:

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

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  passes through the point .  What is the -intercept?

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:

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 ?

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 .

3

14

12

5

7