Answer:
y=8x-25
Explanation:
1) You find the slope by doing y2-y1/x2-x1 (so 7-(-1)/4-3) then you get the slope of 8
2) then you plug in some points using the slope (I'll use the point (3,-1)) : -1=8(3)+b
3) to find "b", you solve: -1=24+b --> b=-1-24 --> b=-25
4) then you put everything together and you get y=8x-25