Mark M. answered 02/18/18
Tutor
4.9
(950)
Retired math prof. Very extensive Precalculus tutoring experience.
f(x) = 2x2
[f(x+h) - f(x)]/h = [2(x+h)2 - 2x2]/h
= [2(x2+2xh+h2) - 2x2]/h
= [4xh + 2h2]/h = h(4x + 2h) / h = 4x + 2h