Factoring. I have the trinomials down pretty good.
But the binomials are getting me stuck.
3x^2+12x=0
please explain! thank you
2007-02-27 12:47:21 · 8 answers · asked by Anonymous in Education & Reference ➔ Homework Help
This one is fairly simple, because there are no numbers without an x coefficient.
In this case, you find common terms between both of them, in this case 3x, and factor that out from both parts. So...
3x(x +4) = 0
Now that you've done that, you can just set both parts equal to 0 and solve
3x = 0
x = 0
x + 4 = 0
x = -4
If you had a term that did not have an x coefficient, then you would have to factor. For example, x^2 +x - 2
Then you would have to factor it down to
(x +2)(x - 1)
by using reverse FOIL (first terms, outside terms, inside terms, last terms)
2007-02-27 12:52:25 · answer #1 · answered by crzywriter 5 · 1⤊ 0⤋
we have 3x^2 + 12x =0
As you can see, they both share a common variable, x. So, we would factor the x out as follow:
x(3x + 12) = 0
From here, if you want to solve for X, set x = 0 and 3x + 12 = 0 and solve
the answers are x = 0 and x = -4.
Hope it's helpful.
2007-02-27 20:54:39 · answer #2 · answered by Anonymous · 0⤊ 0⤋
3x^2+12x=0
>first you need to put this in standard form:
3x^2+12x+0=0
>then unfactor(i call it unfoiling)
(x)(3x+12+0)=0
>now you have 2 mini problems
(x)=0 or (3x+12+0)=0
>you have one of the answers(quadratic formulas have 2 answers most of the time)
3x+12+0=0
>forget about the second 0
3x+12=0
>subtract 12 from each side
3x+12=0
-12 -12
__________
3x= -12
>now divide 3 from each side
3x= -12
_ _
3 3
__________
x= -4
>now you have your 2 answers
x=0 and x= -4
:)
this was hard for me 2
hope it helps, i'm in middle school too
2007-02-27 21:05:23 · answer #3 · answered by funki15munki 2 · 0⤊ 0⤋
You can't really factor this that way into binomials because there isn't just a number withour an x.
i think you probably want to just take out a 3x to get 3x(x+4)
2007-02-27 20:51:50 · answer #4 · answered by a15rivet 2 · 0⤊ 0⤋
Factor out the 3x. You'll be left with (x+4). 3x times the (x+4) equals zero.
2007-02-27 20:52:00 · answer #5 · answered by salsera 5 · 0⤊ 0⤋
3x( x + 4)
3x = 0
x = 0
x+ 4 = 0
x = -4
therefore, x = 0 , x = -4
2007-02-28 02:14:16 · answer #6 · answered by pieces of me 1 · 0⤊ 0⤋
I was going to suggest the quadratic formula, but that wouldn't make sense here since you have no number without an x. Everyone else's answers seem correct.
2007-02-27 20:58:01 · answer #7 · answered by Dorothy K. 7 · 0⤊ 0⤋
you take out 3x so its 3x(x+4)=0
2007-02-27 20:50:50 · answer #8 · answered by nothingisperfectt 1 · 0⤊ 0⤋