Question 922899: What multiplies to be -6 but adds to be 7?
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! What multiplies to be -6 but adds to be 7?
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Equations:
x*y = -6
x + y = 7
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Substitute for "x" and solve for "y"::
(7-y)y = -6
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-y^2 + 7y = -6
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y^2 - 7y + -6 = 0
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y = [7 +- sqrt(49-4*-6)]/2
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y = [7+- sqrt(73)]/2
y = 3.5 + (1/2)sqrt(73) or y = (3.5)-(1/2)sqrt(73)
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Solve for "x" = 7-y ::
If y = 3.5 + (1/2)sqrt(173), x = 10.5-(1/2)sqrt(173)
If y = 3.5 - (1/2)sqrt(173), x = 10.5+(1/2)sqrt(173)
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Cheers,
Stan H.
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