Calculus
posted by Josh .
find tha value of f(x)=x3 where f(x+h)f(x)/h
so far I got 3x2+3hx+h2/h and got stuck from here.

Perhaps you have
f(x) = x^3 (do you have a typo?)
and you want f'(x) ?
f(x+h) = (x+h)^3 = x^3 + 3 x^2h + 3 xh^2 + h^3
subtract x^3
f(x+h) f(x) = 3 x^2h + 3 xh^2 + h^3
divide by h
3 x^2 + 3 xh + h^2
let h >0 for derivative
f'(x) = 3 x^2 (the right answer) 
0.3 (3x + 9)>or equal to 1.2 (x+2)