Question

Find and simplify a) f(a), b) f(a + h) and c)
F(a+h) - f(a) / h ;

1. f(x) = x^2 + 5x -10

Answer 1

f(a+h) = (a+h)^2 + 5(a+h) - 10
f(a) = a^2 + 5a - 10

(f(a+h)-f(a))/h
= (a^2 + 2ah + h^2 + 5a + 5h - 10 - a^2 - 5a + 10)/h
= (2ah + h^2)/h
= 2a + h

Answer 2

oops
(2ah + 5h + h^2)/h
= 2a + 5