Question

How can help me with this operation about Pre-Calculus.
Simplify

Answer 1

If we want to compute
`f(2+h)`, we have to substitute every occurrence of
`x` with
`2+h` in the definition of the function:

`f(x)=x^2-11x \implies f(2+h) = (2+h)^2-11(2+h) = 4+4h+h^2-22-11h = h^2-7h-18`

Similarly, computing
`f(2)` means to substitute the input with 2:

`f(x)=x^2-11x \implies f(2) = 2^2-11\cdot 2 = 4-22 = -18`

So, we have

`f(2+h) - f(2) = h^2-7h-18 - (-18) = h^2-7h`

And finally

`(f(2+h)-f(2))/(h) = (h^2-7h)/(h) = h-7`