Question 405782
3x^2+5x-12=0
(3x+4)(x-3) = 0
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Since the product is zero, one or those factors is zero.
Solve: 
3x+4 = 0
x = -4/3
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x-3 = 0
x = 3
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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
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How do I use the x^2=k for 3x^2+5x-12=0
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Comment:
You don't; you have already solved the
equation by factoring and using the 
zero product method.
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Cheers,
Stan H.
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