Question

factor by grouping
4z^2+12z-az-3a

Answer 1

group the two equations into common terms
(\[(4z^2+12z) + (Za-3a)\]

Answer 2

can you try to factor it from there?

Answer 3

well i got to 4z(z+3)-a(z-3), but I don't know where to go from there

Answer 4

when you took out -a in the second term, this would leave the equation as (z+3)

Answer 5

4z^2+12z-az-3a
4z(z+3)-a(z+3)
(z+3)(4z-a)

Answer 6

so what you should have is 4z(z+3) -a (z+3)

Answer 7

then you can group the other two terms together, (4z-a)(z+3), just like hero said

Answer 8

oh ok, now I get it, I always forget to change the sign on that

Answer 9

Change the sign? You shouldn't need to change any signs if you factor properly

Answer 10

just think of it as you're dividing the entire equation by what you're factoring out, so in this case you're dividing (-za-3a) by -a

Answer 11

if I'm grouping 4z^2+12z-az-3a, I would think it would be (4z^2+12z)-(az-3a)

Answer 12

yeah, try to keep the negatives connected to the terms instead of the equations
so its the first equation set (4z^2+12z) PLUS (-za-3a), you're adding these two different equations together.

what helps me is that i always change all the subtractions to positives, and change the terms to negative so like

4-x is really 4+ (-x)
maybe that'll help you?

Answer 13

yeah i get what you're saying, thanks