Question

please help! composite of functions question!

Answer 1

@hartnn

Answer 2

Please help im having a really hard time with this question!

Answer 3

so you want g(f(-4))

lets first find f(-4)

to get f(-4) you plug in x= -4 in f(x)

what do u get ?

Answer 4

I understand that (g o f) means g(f(x)) but I don't understand where the -1 comes in

Answer 5

plug in x=-4 in
f(x) = x^2+7

Answer 6

its x^2 +7

Answer 7

yes so I did -4^2 - 7, is that correct

Answer 8

why -7 ??
its x^2 +7

\(\Large x^2+7 = (-4)^2 +7 = .. ?\)

Answer 9

Woah sorry! misuse of plus and minus, ok so -4^2 + 7 = -9

Answer 10

hmm...i see that you need
g(f(-1))

and not -4

so, we need to find f(-1) first

\(\Large x^2+7 = (-1)^2 +7 = .. ?\)

Answer 11

ok so that equals to 6

Answer 12

remember

(-1)*(-1) = +1
because multiplying 2 negatives give you a positive!

Answer 13

that is the problem im having, the confusion of whether to plug in -1 or -4, by plugging in -1 i got positive 8

Answer 14

forget -4

the question asks for g(f(-1))

Answer 15

f(-1) = 8 is correct

Answer 16

I dont get what to do from there...

Answer 17

so to find
g(f(-1)) we need
g(8)
makes sense ?

Answer 18

because f(-1) is 8

Answer 19

-4 x 8 = -32

Answer 20

so -32 will be the answer to the problem?

Answer 21

no apparently the answer was 1/2..thanks for trying

Answer 22

lol why was -4 used again ?
we were only half way through...

g(8) = (8-4)/8 = 1/2
...

Answer 23

ooh, ok thanks for helping, i sort of get it, these composite of functions are killing me