Question

Let f(x) = -2x - 7 and g(x) = -4x + 3. Find (f ° g)(-5)
A. 23

B. –53

C. –9

D. 3

Answer 1

Multiply the two functions and replace x with -5 in the result

Answer 2

how u do that

Answer 3

The functions are binomials. Do you know how to multiply binomials?

Answer 4

subtract four from both side

Answer 5

(a+b)(c+d)=ac+ad+bc+bd

Answer 6

ok i have no idea what ur talking bout thxs for the help though

Answer 7

f(x) times g(x)= (-2x-7) times (-4x+3)

Answer 8

And I have no idea what you are talking about when your problem asks you to multiply 2 things and you start talking about subtracting 4 from both sides.

Answer 9

f(x)*g(x)=(-2x-7)(-4x+3)

Answer 10

would that turn into 8x-6x+28x-21

Answer 11

-2x(-4x)=8x^2

Answer 12

so then it will be 8x^2-6x+28x-21. so would i sub all the x's with -5

Answer 13

Combine -6x +28x = 22x

Answer 14

Now replace all the x's with -5

Answer 15

so it would be 8x^2+22x-21 so then it will be 200-110-21. so wouldnt u square the x -5*-5 =25*8=200 then 28*-5=110 then -21

Answer 16

yes

Answer 17

\[8(-5)^2+22(-5)-21=200-110-21=90-21=69\]

Answer 18

ok but 69 is not one of my chosies

Answer 19

Then you might have copied something wrong. Double check.

Answer 20

That is f times g, isn't it?

Answer 21

Or is it f composite g?

Answer 22

If it is f composite g it would be easiest to find g(-5) and substitute that answer into f.

Answer 23

g(-5)=-4(-5)+3=23
f(23)=-2(23)-7=-46-7=-53

Answer 24

well ima try that and see if i get it right thank you for all your help i wrote it just the way i got it