find: f(x+h)-f(x)/ h

Question

when: f(x)=x^2+5x

Answer 1

f(x+h) = (x+h(^2 + 5(x+h)
= x^2 + 2xh + h^2 + 5x + 5h

( f(x+h) - f(x) )/h
= (x^2 + 2xh + h^2 + 5x + 5h - x^2 - 5x) /h
= (2xh + h^2 + 5h)/h
= 2x + h + 5 , h ≠ 0