evaluate the limit

as lim h goes to 0

((2+h)^3 - 8)/h

the answer is twelve but I don't know how to factor out the cube

expand the (2+h) term

(2+h)(4+4h+h^2)
8+8h+2h^2+4h+4h^2+h^3
then, in the numerator, subtract 8 so the result is
12h+6h^2+h^3
divided by the denominator h
12+6h+h^2 and the limit as h>>zero is 12