SOLUTION: Use the following quadratic equation to complete parts a and b below. You must show all work. x2 + 4x - 21 = 0 a. Solve by factoring. b. Solve using the quadratic formula.

Question 406079: Use the following quadratic equation to complete parts a and b below. You must show all work.
x2 + 4x - 21 = 0
a. Solve by factoring.
b. Solve using the quadratic formula.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
x^2 + 4x - 21 = 0
a. Solve by factoring.
x^2+7x-3x-21 = 0
x(x+7)-3(x+7) = 0
(x+7)(x-3) = 0
x = -7 or x = 3
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b. Solve using the quadratic formula.
x = [-4 +- sqrt(16 - 4*1*-21)]/2
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x = [-4 +- sqrt(16+84)]/2
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x = [-4 +- 10]/2
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x = [-2+- 5]
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x = -7 or x = 3
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Cheers,
Stan H.
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