Question

Evaluate f(x+h)-f(x)/h and simplify if f(x)=x^2-2x ...?

Answer 1

$\frac{f(x+h)-f(x)}{h}= \\ = \frac{(x+h) ^{2}-2(x+h)-( x^{2} -2x) }{h}= \\ = \frac{ x^{2} +2hx+ h^{2}-2x-2h+2x }{h}= \\ = \frac{2hx+ h^{2}-2h }{h}= \\ = \frac{h(2x+h-2)}{h}=$
= 2 x + h - 2