Question

If f(x)=7-x^2 and g(x)=x-4 ... [f*g](x)=?

Answer 1

=f[g(x)]
=f(g(x)= 7-(g... ?
Is that right so far?

Answer 2

[f*g](x)= 7- (x-4)^2
solve it furhter

Answer 3

7-x^2-16?

Answer 4

is that right?

Answer 5

[f*g](x)= 7- (x-4)^2
= 7-(x^2+16-8x)
do it further now

Answer 6

where did 8x come from?

Answer 7

how would i get rid of the parentheses?

Answer 8

just multiply the negative sign with each term inside the parantheses

Answer 9

So...
7+x^2-112+56x

Answer 10

sorry: 7-x^2

Answer 11

7-x^2-16+8x

Answer 12

how did you get 16 and 8? do you not multiply 7 to those numbers?

Answer 13

no i m not multiplying 7 to those numbers.
i got 16 and 8 by the following formula
\[(a-b)^{2} = a ^{2} +b ^{2}-2ab\]

Answer 14

so if I had [g#f](x)
i would start it by saying x-4(7-x^2) right?

Answer 15

# is supposed to be *

Answer 16

yes exactly

Answer 17

thanks so much!

Answer 18

welcome