Question

How do you evaluate `f(n-1)` if `f(x)=2x^2-x+9`?

Answer 1

`f(n-1)=2n^2-5n+12`

Explanation:

replace all the `xs` with `(n-1)` and simplify

`f(x)=2x^2-x+9`

`f(n-1)=2(n-1)^2-(n-1)+9`

`f(n-1)=2(n^2-2n+1)-(n-1)+9`

`f(n-1)=2n^2-4n+2-n+1+9`

`f(n-1)=2n^2-5n+12`