Kindly check below
1) Whenever there is a coefficient "a" such as 0
2) Note that this graph resembles an absolute value function, y=|2x| but it is not. Therefore, we can plot the graph this way.
In our original function the points are (0,0), (2,4), (-2,4) in our compressed ones the points are (0,0), (2,2), and (-2,2)