How to find x or y intercept

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Math › How to find x or y intercept

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1

A straight line passes through the points and .

What is the -intercept of this line?

Explanation

First calculate the slope:

The standard equation for a line is .

In this equation, is the slope of the line, and is the -intercept. All points on the line must fit this equation. Plug in either point (1,3) or (2,2).

Plugging in (1,3) we get .

Therefore, .

Our equation for the line is now:

To find the -intercept, we plug in :

Thus, the -intercept the point (4,0).

2

Find the x-intercept of the line .

Explanation

Recall that an x-intercept occurs when the line crosses the x-axis. Thus, the y-coordinate of the x-intercept must be .

Plug in for the y-value.

The x-intercept is located at .

3

What is the y-intercept of the line with the equation ?

Explanation

You should recognize that the given equation is in the point-slope form.

In order to find the y-intercept, rearrange the equation into slope-intercept form, .

Since, , the y-intercept must be located at

4

Find the y-intercept of the line .

Explanation

Recall that at the y-intercept, the line crosses the y-axis. This means that at the y-intercept, the value of the x-coordinate is .

Plug in for into the equation to find the y-intercept.

The y-intercept for this line is .

5

Find the x-intercept(s) for the circle

The circle never intersects the x-axis

Explanation

The x-intercepts of any curve are the x-values where the curve is intersecting the x-axis. This happens when y = 0. To figure out these x-values, plug in 0 for y in the original equation and solve for x:

adding 0 or 0 square doesn't change the value

take the square root of both sides

this means there are two different potential values for x, and we will have to solve for both. First:

add 4 to both sides

Second: again, add 4 to both sides

Our two answers are and .

6

What is the y-intercept of a line with the equation ?

Explanation

You should recognize that the given equation is in the point-slope form.

In order to find the y-intercept, rearrange the equation into slope-intercept form, .

Since, , the y-intercept must be located at

7

Find the y-intercept of the line .

Explanation

Recall that at the y-intercept, the line crosses the y-axis. This means that at the y-intercept, the value of the x-coordinate is .

Plug in for into the equation to find the y-intercept.

The y-intercept for this line is .

8

Find the x-intercept of the line .

Explanation

Recall that an x-intercept occurs when the line crosses the x-axis. Thus, the y-coordinate of the x-intercept must be .

Plug in for the y-value.

The x-intercept is located at .

9

Find the x-intercept for the line .

Explanation

Start by putting the equation into form, where is the slope, and is the y-intercept.

By definition, the x-intercept is where the line crosses the x-axis. As such, the y-coordinate of this point must be .

Plug in for in the equation for this line.

Now, solve for .

The x-intercept is found at .

10

Find the x-intercept for the line

.

Explanation

To find the x-intercept, plug in 0 for y, since the x-axis is where y = 0

subtract 5 from both sides

multiply both sides by -3

The x-intercept is

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