Question

Factor completely

2x^3 + 2x^2 - 84x

Answer 1

@jim_thompson5910 can you help

Answer 2

show me how far you got

Answer 3

Im not sure how to start it, do I find what multiplies to 84 and subtracts to 2?

Answer 4

what is the GCF in this case?

Answer 5

84

Answer 6

what is the common factor between each term

Answer 7

I don't know how to find that..

Answer 8

what is the GCF of 2, 2, 84 ?

Answer 9

2?

Answer 10

nevermind... I dont remember how to find that

Answer 11

they all have an x in common as well

Answer 12

so the overall GCF is 2x

Answer 13

so when you factor out the GCF you go from

2x^3 + 2x^2 - 84x

to

2x(x^2 + x - 42)

Answer 14

now you must factor x^2 + x - 42

Answer 15

so whatever multiplies to 42 and subtracts to 1?

Answer 16

correct

Answer 17

So (x+1)(x-42)

Answer 18

-42 + 1 is not 1

Answer 19

oh, i forgot about the negative...

Answer 20

try another factor pair

Answer 21

(x-7)(x+6)

Answer 22

close, it should be +7 and -6 since

+7 - 6 = +1

Answer 23

so the final answer is

2x(x+7)(x-6)

Answer 24

Okay thanks:)

Answer 25

yw