The equation that has a slope of -4 and passes through the point (1,-2) would be: y=-4x+2
since y=mx+b,
m=-4
and you know one point that the line passes through-->y=-2, x=1
you can use m, y and x to find the b (the y-intercept)
y=mx+b
(-2)=(-4)(1)+b
2=b
So if you put together the slope that is given, and the y-intercept that you found using the point: y=(-4)x+2