Question 274717: solve the equation by completing the square x2+3x-9=0.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! solve the equation by completing the square
x^2+3x-9=0
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x^2 + 3x + ? = 9 + ?
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Complete the square:
x^2 + 3x + (3/2)^2 = 9 + (3/2)^2
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Factor:
(x+3/2)^2 = (36/3)+(9/4) = 45/4
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x + (3/2) + (9/2)sqrt(5) or x+(3/2) = (-9/2)sqrt(5)
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x = (-3+9sqrt(5))/2 or x = (-3-9sqrt(5))/2
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Cheers,
Stan H.
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