Find and simplify a) f(a), b) f(a + h

c) f(a+h)-f(a) / h ; h=0

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

HELP.

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

so
f(a+h)= a^2 + 2 a h + h^2 + 5 a + 5 h - 10
f(a) = a^2 + 5 a - 10
-------------------------subtract
2 a h + h^2 + 5 h
divide by h

2 a + h + 5
let h --> 0

= 2 a + 5

This is really calculus, the definition of the derivative at x = a