The slope of the line is 3/2.
This is because you have to move the x value to the right side to follow the parent function y=mx+b. When you move the x to the right, the equation becomes -2y=-3x+8. In order to make y the same as the parent function, you divide -2 on both sides. This makes the final equation y=3/2x-4. According to this, the slope is 3/2.