SOLUTION: Solve the following problems by factoring. 1) 8x^3+1=0 2) x^4-7x^2-8=0 Factor: 1) x^4-x^2-72 2) 2x^4-16x

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: Solve the following problems by factoring. 1) 8x^3+1=0 2) x^4-7x^2-8=0 Factor: 1) x^4-x^2-72 2) 2x^4-16x      Log On


   

Question 408633: Solve the following problems by factoring.
1) 8x^3+1=0
2) x^4-7x^2-8=0
Factor:

1) x^4-x^2-72
2) 2x^4-16x
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Solve the following problems by factoring.
1) 8x^3+1=0
(2x+1)(4x^2-2x+1) = 0
x = -1/2 or
4x^2-2x+1 = 0
x = [2 +- sqrt(4-4*4*1]]/8
x = [2 +- sqrt(-12)]/8
x = [2 +- 2sqrt(3)i]/8
x = (1/4) +- (1/4)sqrt(3)i
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2) x^4-7x^2-8=0
(x^2-8)(x^2+1) = 0
x = +-2sqrt(2) or x = +-1
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Factor:
1) x^4-x^2-72
(x^2-9)(x^2+8)
(x-3)(x+3)(x^2+8)
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2) 2x^4-16x
2x(x^3-8)
= 2x(x-2)(x^2+2x+4)
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Cheers,
Stan H.
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