Question

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

Answer 1

We just subsitute `x` with `n-1` and carrying out all algebraic operations we get `f(n-1)=2n^2-5n+12`

Explanation:

We just subsitute `x` with `n-1` and carry out all algebraic operations.

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

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

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

= `2n^2-4n+2-n+1+9`

= `2n^2-5n+12`