Question

A linear function has the same y-intercept as x + 4y = 12 and its graph contains the point (9,5). Find the slope of the linear function.

a. 2/9

b. 9

c. -2/9

d. 5/9

Answer 1

The answer is A: a slope of 2/9

First you need to change find the y-intercept by converting the standard form equation to slope-intercept form. The goal is to isolate y:

x + 4y = 12

x + 4y - x = 12 - x

4y = 12 - x

4y / 4 = 12/4 - x

y = 3 - x

Change so that the slope is before the intercept:

y = -x + 3

Now we know that the y-intercept is 3.

Use the slope equation, which is y2 - y1/x2 - x1, is find the slope:

5 - 3/9 - 0 = 2/9

So, the slope is 2/9!