Question

If f(x) = 3x2 - x, find f(-2).

Answer 1

\(\large\color{royalblue}{ f(x) = 3x^2 - x }\).

If I was to find \(\large\color{red}{ f(-4) }\) I would plug in 4 for x, like this:

\(\large\color{royalblue}{ f(\color{red}{-4}) = 3(\color{red}{-4})^2 - (\color{red}{-4})}\)

\(\large\color{royalblue}{ f(\color{red}{-4}) = 3(16) +4}\)

\(\large\color{royalblue}{ f(\color{red}{-4}) = 48+4}\)

\(\large\color{royalblue}{ f(\color{red}{-4}) = 52}\)

Answer 2

find \(\large\color{red}{ f(-4) }\) the same exact way, but you are plugging not -4, but -2 for x.

Answer 3

the answer = 14?

Answer 4

oh, typo in a second line, first reply.
I would plug in `-` 4 for x.

Answer 5

had too many typos, I deleted my last reply, but \(\large\color{royalblue}{ f(\color{red}{-2}) = 14}\) is correct.

Answer 6

\(\large\color{royalblue}{ f(\color{red}{x}) = 3(x)^2-x}\)

\(\large\color{royalblue}{ f(\color{rd}{-2}) = 3(-2)^2-(-2)}\)

\(\large\color{royalblue}{ f(\color{rd}{-2}) = 3(4)-(-2)}\)

\(\large\color{royalblue}{ f(\color{rd}{-2}) = 12+2}\)

\(\large\color{royalblue}{ f(\color{red}{-2}) = 14}\)