Question

If f(x)=x2-2x+9, and g(x)=8x, what is (f*g)(-4)

Answer 1

9

Answer 2

sorry but the answer is one of these :
a:111,
b. 144,
c. 120,
d. 129.
Just can't figure out how to get the answer

Answer 3

you have f*g which means f multiplied by g

Answer 4

maybe you wrote the problem wrong

Answer 5

\[\large \color{orangered}{f(x)=x^2-2x+9}\]\[\large \color{royalblue}{g(x)=8x}\]

\[\large \color{orangered}{f(\color{royalblue}{g(x)})=\color{royalblue}{g(x)}^2-2\color{royalblue}{g(x)}+9}\]
I Assume this is a composition of functions problem yes?

What we want to do is, take the blue function, and stuff it into the orange function.
See how I stuck the blue function in for each x in f(x)?

Answer 6

\[\large \color{orangered}{f(\color{royalblue}{8x})=\color{royalblue}{(8x)}^2-2\color{royalblue}{(8x)}+9}\]Understand the process?
I know it can be a little confusing at first.

Answer 7

it is not f o g it was written f*g

Answer 8

I'm sorry it is f o g

Answer 9

then what zepdrix wrote is correct

Answer 10

thank you