Given that f(x) = −x + 4 and g(x) = −2x − 3, solve for f(g(x)) when x = 2.

−14

−7

7

11

Question

Given that f(x) = −x + 4 and g(x) = −2x − 3, solve for f(g(x)) when x = 2.

 −14

 −7

 7

 11

anonymous · Answer

Substitute x into your equation g(x) then using the value you find use it for the value of x in your f(x)

jenniferjuice · Answer

wait what do i d0?!?!

kinggeorge · Answer

When they're asking for $f(g(x))$, they want you to first find $g(x)$, and plug that value in for $f(x)$. So can you tell me what $g(2)$ is?

jenniferjuice · Answer

-7?

kinggeorge · Answer

Right. That's $g(2)$. Now take that value, and plug it into $f(x)$. So what's $f(-7)$?

jenniferjuice · Answer

-3?

kinggeorge · Answer

That's not quite right. $f(x)$ is given by $f(x)=-x+4$. So when you plug in $-7$, you get$$f(-7)=-(-7)+4$$The two negatives actually cancel each other out. So you'll actually get$$f(-7)=-(-7)+4=7+4=11$$

jenniferjuice · Answer

thank you

kinggeorge · Answer

So now, if they instead asked for $f(g(x))$ when $x=3$ could you do that?

jenniferjuice · Answer

is it 1?

kinggeorge · Answer

That would be what you get if $x=-3$ instead of $3$. For positive $3$, you would get$$g(3)=-9$$and$$f(-9)=13$$For a final result of $13$.

kinggeorge · Answer

With $x=-3$, you have$$g(-3)=3$$and$$f(3)=1$$

jenniferjuice · Answer

oh