Question

Complete the point-slope equation of the line through (-4,8) and (4,4)

Answer 1

Point Slope Form looks like this:

$y-y_{1} = m(x-x_{1})$

First, we need to find the m value, or slope. We can do this by using this equation:

$y_{2} - y_{1 }= x_{2} - x_{1}$

4 - 8 / 4 + 4 = -4/8 = -1/2
m = -1/2

Now, select one of the coordinate points, input those values and m, and solve for b.

4 = -1/2(4) + b
4 = -2 + b
Add 2 to both sides.
6 = b

y = -1/2x + 6

Now, input any number for x (I prefer 0, the y-intercept), and solve for y.

y = -1/2(0) + 6
y = 6

(0, 6)

After doing that, you can input that coordinate point into Point-Slope Form.

y - 6 = -1/2(x - 0)