SOLUTION: using college math - quadratic equations - i factored this out like this: 3x^2+5x-12=0 (3x+4) (x-3) -4 +3 x= -4 x=3 1)now i need to use the form x^2 = k, then = +-

Question 405782: using college math - quadratic equations - i factored this out like this:
3x^2+5x-12=0
(3x+4) (x-3)
-4 +3
x= -4 x=3
1)now i need to use the form x^2 = k, then = +- sqrt k
how do i do that?
The only example i have is this, but i don't understand where they got the 6 and the 2 from.
x^2=72
x=+-sqrt72
x = +-6sqrt2
How do i use the x^2=k for 3x^2+5x-12=0

Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
3x^2+5x-12=0
(3x+4)(x-3) = 0
---
Since the product is zero, one or those factors is zero.
Solve:
3x+4 = 0
x = -4/3
----
x-3 = 0
x = 3
--------------------------------
1)now i need to use the form x^2 = k, then = +- sqrt k
how do i do that?
The only example i have is this, but i don't understand where they got the 6 and the 2 from.
x^2=72
x=+-sqrt72
x = +-sqrt(36*2)
x = +-[sqrt(36)*sqrt(2)]
x = +-6sqrt2
==========================================
How do I use the x^2=k for 3x^2+5x-12=0
---
Comment:
You don't; you have already solved the
equation by factoring and using the
zero product method.
=========================
Cheers,
Stan H.
=============

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