10 - 2x
10 - 2(7)
= 10 - 14
= -4
The y-intercept is the "b" in the slope-intercept form of y=mx+b. Based on the equation you wrote, you can substitute each of your known values into the slope-intercept form.
384
X 4 =
1536
5384
x 4 =
21536
40x = 1500
x = 37.5
37.5% i believe