Math
posted by Hannah on .
if f(x) = 2x^2 + 5x,
find f(x+h)  f(x) / h and simplify.
I started to do this but then got lost.
2(x+h)^2 + 5x + 2x^2 + 5x all over h
4x^2 + 4xh + h^2 + 5x + 2x^2 + 5x

2[x^2 + 2 x h + h^2] + 5x + 5 h
2 x^2 +4 xh + 2 h^2 + 5 x + 5 h
2x^2 5x
= 4 x h + 2 h^2 + 5 h
divide by h
4 x +2 h + 5
check  limit as h> 0 should be derivative
4 x^2 + 5 yes check 
Well the answer choices were
1) 4x + 5xh + h^2 + 5h
2) 4x + 5h + 4h^2
3) 4x + 5 + 4h^2 + 5h
4) None of the above
So the answer is none of the above correct? 
The answer is 4x^2 + 5 correct?