Question

f(x) = -4x + 7 and g(x) = 10x - 6, find f(g(x)).

Answer 1

f(g(x)) means you plug in g(x) into the x's in f(x)! It's kinda weird!

Answer 2

I don't understand how to like solve the answer though, can you help me? @iPwnBunnies

Answer 3

I'm really bad at Algebra. I'm taking Algebra 2 but i'm only n 8th grade

Answer 4

Sure. Let me just do the plugging in, I'm sure you can simplify.
f(g(x)) = -4(10x-6) + 7. Do you see now?
We plugged in the function g(x) into the x's in f(x).

Answer 5

so then you just solve for x?

Answer 6

-40x+31?

Answer 7

Yes! I don't think you solve for x.
You keep it as f(g(x)) = -40x + 31. Good job!

Answer 8

what about this one? f(x) = 9x - 2 and g(x) = -x + 3. Find f(g(x)).

Answer 9

i don't know how to do that first part that you did but after that part i can solve the equation

Answer 10

Do the exact same thing I just showed you. I'll be here.

Answer 11

ok ill try it, when I'm done ill show you

Answer 12

Ok/

Answer 13

so its 9(-x+3)-2

Answer 14

Yes! Now expand it, simplify, and set it equal to f(g(x))

Answer 15

simplified to f(g(x))=-9x+25?

Answer 16

Yep. Good work man. :)

Answer 17

thank you!!

Answer 18

I've done most of the rest of my problems, would you mind checking them for me? I do online school and i don't really have anyone here to help me

Answer 19

@iPwnBunnies

Answer 20

Ok

Answer 21

f(x) = x2 - 8x + 5. Find f(-1).

Answer 22

and i got 14? @iPwnBunnies

Answer 23

Correct.

Answer 24

f(x) = x - 2 and g(x) = x2 - 7x - 9. Find f(g(-1)).
and i got -3

Answer 25

Yes, correct!

Answer 26

f(x) = x + 8 and g(x) = x2 - 6x - 7. Find f(g(2)).
and i got -7

Answer 27

Correct.

Answer 28

and now this one I'm having trouble with as well

Answer 29

f(x) = 2x - 6 Solve f^-1(x) when x = 2.

Answer 30

f^(-1)(x) is the inverse of f(x). What do you is change places of y and x in f(x). Solve for y again.

Answer 31

What you do*

Answer 32

wait I don't understand, can you give me an example? I'm sorry

Answer 33

Sure. For example, we have f(x) = 3x + 2. To find the inverse, rewrite f(x):
y = 3x + 2
2. Change the places of y and x: x = 3y + 2
3. Solve for y, and replace it with f^(-1)(x): y = (x-2)/3 = f^(-1)(x)

Answer 34

ok… so the answer to the one i was doing, is 4 correct?

Answer 35

Correct, great job man.

Answer 36

ok, thank you! Last one i promise! haha f(x) = 2x + 2. Solve f-1(x) when x = 4

Answer 37

Do the same process I showed you to get the inverse of f. Plug in 4 into the inverse.

Answer 38

so the answer would be one?

Answer 39

Yup.

Answer 40

thank you so much!!! your the best!!!

Answer 41

No prob.