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

so

(-2x - 7)(-4x + 3)

use FOIL

Answer 2

8x-4 ?

Answer 3

what is -2x * -4x?

Answer 4

8x

Answer 5

8x^2

Answer 6

remmeber when you multiply 2 x's...it's x time x...also known as x²

so -2x * -4x...is 8x²

Answer 7

good...okay now what's -2x * 3?

Answer 8

you cant multiply them together bc it doesn't have an x right ?

Answer 9

you're thinking of adding and subtracting...you cant add or subtract un-like terms...but multiplying you can multiply basically anything....-2x * 3....you would just multiply the numbers....so -2 times 3 is -6...and bring the x with it....so -6x

Answer 10

use that same thinking...to find out...what is -7 * -4x?

Answer 11

28x

Answer 12

correct...and finally what is -7 * 3?

Answer 13

-21

Answer 14

so -6x*28x*-21 ? and sub x for -5 ?

Answer 15

no im so wrong i just tried it

Answer 16

good,...not that you know the foil method...let me tell you...i've been telling you something completely different than what you need ...but you learned a new skill...lol...i'm sorry ..lets solve this correctly now this is actually easier than you think

Answer 17

again im sorry...what you do....is plug -5 in for x in g(x)

Answer 18

-4(-5) + 3 = 23

now plug 23 in for x in f(x)

Answer 19

-2(23) - 7

-46 - 7

-53

Answer 20

again sorry about the confusion..i should have read it better before answering....but You learned a new skill :)

Answer 21

lol okay thankyou