Question

What is the value of f(x) = 9x when x = -2?

Answer 1

9 * -2 = -18

Answer 2

are you sure its not positive ? /:@Catlover5925

Answer 3

@Catlover5925

Answer 4

\(\large\color{black}{ f(x)=9x }\)
to find f(-3), you plug in -3 for x.
\(\large\color{black}{ f(-3)=9(-3)=-27 }\) so \(\large\color{black}{ f(-3)=-27 }\)

to find f(1), you plug in 1 for x.
\(\large\color{black}{ f(1)=9(1)=9 }\) so \(\large\color{black}{ f(1)=9 }\)

to find f(0), you plug in 0 for x.
\(\large\color{black}{ f(0)=9(0)=0 }\) so \(\large\color{black}{ f(0)=0 }\)


see?

to find f(-2), you plug in -2for x.
\(\large\color{black}{ f(-2)=9(-2)=? }\) so \(\large\color{black}{ f(-2)=? }\)

Answer 5

ohh okkay thank @SolomonZelman so it would be -18? but my answer choices dont have a negative 18 only positive 18

Answer 6

yes it is -18.

Answer 7

why do you think it would be positive??? it is a negative * a positive....
if it was a negative * negative then it would be positive

Answer 8

maybe it is \(\large\color{black}{ f(x)=9^x }\) ?

Answer 9

yes that @SolomonZelman

Answer 10

so to find f(-2), plug in -2 for x into the function.

Answer 11

There is a rule, \(\LARGE\color{blue}{ a^{-c}= \frac{1}{a^c} }\) and applying this rule to
\(\Large\color{black}{ 9^{-2}= \frac{1}{a} }\) what do you get?

Answer 12

\(\Large\color{black}{ 9^{-2}= ? }\)

Answer 13

oh ok now that makes more sence!! now it would be positive

Answer 14

yes:) but an 18 though:)

Answer 15

alright thanks guys @Catlover5925 @SolomonZelman