Question

Can someone please help with the last problem

Answer 1

Answer:

  18x +9h

Step-by-step explanation:

Such problems are tedious, but not difficult. The trick is to avoid making mistakes in the algebra.

  $\dfrac{f(x+h)-f(x)}{h}=\dfrac{(9(x+h)^2)-(9x^2)}{h}\\\\=\dfrac{9(x^2+2xh+h^2)-9x^2}{h}=\dfrac{18xh+9h^2}{h}=\boxed{18x+9h}$