Question

Help would be very much appreciated

Answer 1

$\dfrac{f(2+h)-f(2)}{h}=\dfrac{(2+h)^2+2(2+h)-1-(2^2+2\cdot2-1)}{h}=\\\\=\dfrac{4+4h+h^2+4+2h-1-(4+4-1)}{h}=\dfrac{h^2+6h+7-7}{h}=\dfrac{h^2+6h}{h}=h+6$