Investigate the function of a line, y = x:
Investigate the function parabola, y = x^2:
Why do you think we do the opposite motion when the function translates along the x axis? Hint: Look at . Notice that when the graph moves along the positive x direction the function looks like (x - h) but when the function moves in the negative x direction the function looks like (x + h). Why do you think this happens?