Answer
$y=0.25x+7.75.$
Work Step by Step
We know that two non-vertical lines are perpendicular if the product of their slopes is $-1$. Hence here the slope is $m=\frac{-1}{-4}=0.25$
We know that if the slope of a line is $m$ and it contains $P_1(x_1,y_1)$, then its equation is: $y-y_1=m(x-x_1).$
Hence here: $y-7=0.25(x-(-3))\\y-7=0.25x+0.75\\y=0.25x+7.75.$
