So,
We need the equation y = mx + b. We need to know the slope and the y-intercept.
The question already gives us the slope: 6.
y = 6x + b
If we substitute the given solution for x and y, we will be able to solve for b.
-7 = 6(-8) + b
Distribute
-7 = -48 + b
Add 48 to both sides
41 = b
y = 6x + 41