If P(x,y) is a point in the x-y plane then reflection maps this to Q(-x,y) and compression maps this to R(-x,y/8).
If we know the equation for all points P then we can work out what the new equation for all points R would be.
Take a simple example for P: y=x+1, then R=(1-x)/8.
The picture below shows how the point P(2,3) is transformed into the point R(-2,⅜).
The red line represents the equation y=x+1; the blue line represents y=1-x; the green line represents y=(1-x)/8.