Question

Okay here's another but at least I got the GCF out

24r^3 + 166r^2 - 168r

I factored out 4r to get:
4r (6r^2 + 29r - 42)

but of course this is where I get stuck

Answer 1

166/4 = 83/2

Answer 2

I'm sorry wrote it wrong, ahhhhh, it's 116r not 166r

Answer 3

original problem is 24r^3 + 116r^2 - 168r

Answer 4

now u factorise the quadratic equation in the bracket...

Answer 5

does the problem allow you to use the quadratic method of finding r?

Answer 6

then i factored out 4r to get 4r(6r^2 + 29r - 42)

Answer 7

ur factors are correct
now factior the quadratic

Answer 8

now looking at 6r^2+29r-42
we need to find two factors of 6(-42) that multiply to be 6(-42) and add up to be 29
6(-42)=36(-7)
36-7=29
so we have 6r^2+36r-7r-42
now factor by grouping

Answer 9

hint: factors of -42 are +6 and -7

Answer 10

i got (6r-7)(r+6)

Answer 11

right

Answer 12

so don't forget the 4r and you are done

Answer 13

by jove you've got it!

Answer 14

so it's 4r(6r-7)(r+6)

Answer 15

yep

Answer 16

thanks guys so much