distribute the 4 in the numerator an ah in the denominator...
you get
4a - 4a - 4h / [a^2h + ah^2) ]
then i cancelled all the a's and cancelled 4 -4
and got -4h / ah + h^2
now on the computer i entered -4 for the numerator and it came out to be correct....
but my denominator is wrong, why? what did i do wrong?