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

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Answer 1 · 2017-02-14T10:30:31

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

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

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

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

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

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

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

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