Question

Can anyone check a few questions for me?

1.If f(x)=-2x+7 and g(x)=x^2-2, f(g(3))=-7?

2. If f(x)=(2^x)-1 and g(x)=(x^2)-1, (f o g)(3)=63?

Answer 1

First find f(g(x)) and then plug in 3.

Answer 2

the 2nd one?

Answer 3

\[f(g(x)) = -2(x^2-2)+7\] now find f(g(3)) it's the same thing

Answer 4

and also you can find g(3) first and then plug that into f(g(x))

Answer 5

Sure, that works to

Answer 6

I put g(3) first

Answer 7

Basically it's telling you to take g(x) and plug it in f(x)

Answer 8

Then put that into f(x)

Answer 9

So I got

g(3)=-

f(g)(3)=-2(7)+7=-7

Answer 10

@Nnesha

Answer 11

loooks good :)

Answer 12

Now the 2nd one

Answer 13

How do I even plug in that one correctly?

Answer 14

oky for 2nd again first do g(3)
replace x by 3 for g(x)

Answer 15

What happens if I first plug g into f?

Answer 16

(2^x-1)-1?

Answer 17

I mean (2^x^2-1)-1

Answer 18

okay back so for second one first you have to replace x by 3 into g(x)

Answer 19

that can be hard bec 2^x^2

Answer 20

idk if that's work or not
but we did like this at school

Answer 21

So if it was put 3 into (g)x then, take that value to f(x)

i get 3(g)x=8 right?

Answer 22

then 2^8-1=255?

Answer 23

if i put g(x) into f(x) first you get

2^(x^-1)-1

Answer 24

2^(x^2-1)-1

Answer 25

so same thing right?

Answer 26

a
3 power 2 is 9
and 9 -1 equal 8