SOLUTION: 8x^3-125=0

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Question 1022393: 8x^3-125=0
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
8x%5E3-125=0


%282x%29%5E3-125=0


%282x%29%5E3-5%5E3=0


%282x-5%29%28%282x%29%5E2%2B%282x%29%2A5%2B5%5E2%29=0 Use the difference of cubes factoring formula


%282x-5%29%284x%5E2%2B10x%2B25%29=0


2x-5=0 or 4x%5E2%2B10x%2B25=0


Solving 2x-5=0 yields x+=+5%2F2=2.5


Solving 4x%5E2%2B10x%2B25=0 produces NO real solutions (the two solutions are imaginary). Use the quadratic formula to determine this.


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So the only solution is x+=+5%2F2 or x+=+2.5. The two are equivalent but in different forms.