Question 535336: How do I solve 125x^3 + 343 = 0?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! solve 125x^3 + 343 = 0
Modify:
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(5x)^3 + 7^3 = 0
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Factor:
(5x+7)((5x)^2-(5x)(7)+7^2) = 0
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(5x+7)(25x^2-35x+49) = 0
One of those factors must be zero:
If 5x+7 = 0
x = -7/5
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If 25x^2-35x+49 = 0
x = [35 +- sqrt(35^2 - 4*25*49)]/50
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x = [35 +- sqrt(-3675)]/50
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x = (7/10) +- (60.62/50)i
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Cheers,
Stan H.
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