First use the slope formula to find the slope of -4. y2-y1/x2-x1 which looks like this: 9-(-7)/-1-3 = 16/-4 = -4. Now use that slope and one of the points to sub into the y = mx+b to solve for b and then use that b and your slope of -4 to rewrite the equation. I chose (-1,9) as my point to get 9=-4(-1)+b. Solve for b to get b = 5. Therefore, the equation of the line is y = -4x + 5
