Question

Let f(x) = x - 2 and g(x) = x^2 - 7x - 9. Find f(g(-1)).
Select one:
a. -21
b. -3
c. 3
d. 21

Answer 1

So you deal with the inside function first...g(x) ..when you plug -1 in for the 'x' in g..what does the equation come out to?

Answer 2

I literally have no idea how to do this, I literally don't understand at all so can you tell me the first step

Answer 3

Sure!

So first step...is look at the inside function...in f(g(-1)) this is g(x)...so look at your 'g' equation

g(x) = x^2 - 7x - 9

when it has g(-1) it's telling you to replace every 'x' you see in the equation with that number (-1) ...so

g(-1) = (-1)^2 - 7(-1) - 9
g(-1) = 1 + 7 - 9
g(-1) = ?

Answer 4

If I plug in -1 for g(x) it's -1^2-7(-1)-9
= 1 + 7 - 9 = -1

Answer 5

So -1

Answer 6

Right...now what you do...is you take what you got (-1) and you plug that into your OUTSIDE function now...here...that would be f(x)

f(x) = x - 2

Plug in the -1 you just got for every 'x' you see....

f(-1) = -1 - 2
f(-1) = ?

Answer 7

-3

Answer 8

And that would be correct :)