Question

If f(x)=x^2 -3x-4, find f(a+h)-f(a)

Answer 1

Replace every x with a+h
\[\Large f(x)=x^2-3x-4\]
\[\Large f(\color{red}{x})=(\color{red}{x})^2-3(\color{red}{x})-4\]
\[\Large f(\color{red}{a+h})=(\color{red}{a+h})^2-3(\color{red}{a+h})-4\]

Answer 2

Now expand out and simplify
\[\Large f(a+h) = (a+h)^2 -3(a+h)-4\]

Answer 3

Tell me what you get

Answer 4

@jim_thompson5910

Answer 5

I got a^2+2ah+h^2-3a-3h-4

Answer 6

good

Answer 7

what is f(a) equal to?

Answer 8

I don't know

Answer 9

just replace every x with 'a' in f(x)

Answer 10

okay thankyou

Answer 11

\[\Large f(a+h) = a^2+2ah+h^2-3a-3h-4\]
\[\Large f(a) = a^2-3a-4\]

Answer 12

now tell me what \[\Large f(a+h)-f(a)\] is equal to

Answer 13

2ah+h^2-3h

Answer 14

correct