Question

Find the value of y so that the line passing through (9, 0) and (3, y) has a slope of -1/2.

Answer 1

Well you know slope is

\[\large m = \frac{ y_2 - y_1 }{ x_2 - x_1 }\]

Your 2 points are given and we know slope is -1/2

9 , 0 = x1 , y1
3 , y = x2 , y2

So plugging all this in we have

\[\large -\frac{1}{2} = \frac{ y - 0 }{ 3 - 9 }\]

Now just solve for 'y'