SOLUTION: How do you completely factor out 8a^3+27b^3 or is it prime?

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Question 118314: How do you completely factor out 8a^3+27b^3 or is it prime?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
8a%5E3%2B27b%5E3 Start with the given expression


%282a%29%5E3%2B%283b%29%5E3 Rewrite 8a%5E3 as %282a%29%5E3 and 27b%5E3 as %283b%29%5E3

%282a%2B3b%29%284a%5E2-6ab%2B9b%5E2%29 Now factor using the sum of cubes. Remember the sum of cubes formula is x%5E3%2By%5E3=%28x%2By%29%28x%5E2-xy%2By%5E2%29


So 8a%5E3%2B27b%5E3 factors to %282a%2B3b%29%284a%5E2-6ab%2B9b%5E2%29