Answer
$-2x+y=5.$
Work Step by Step
We know that by the Slope Formula: if $P_1(x_1,y_1)$ and $P_2(x_2,y_2)$ are on a line, then the slope is: $m=\frac{y_2-y_1}{x_2-x_1}$.
Hence here: $m=\frac{3-(-7)}{-1-(-6)}=\frac{10}{5}=2.$
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: $y-3=2(x-(-1))\\y-3=2(x+1)\\y-3=2x+2\\y=2x+5\\-2x+y=5.$
