SOLUTION: Factor Completely: 8x^3 + 27y^3

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Question 1875: Factor Completely: 8x^3 + 27y^3
Answer by longjonsilver(2297) About Me  (Show Source):
You can put this solution on YOUR website!
8 is 2%5E3 and 27 is 3%5E3 so, we can write the statement as:
%282x%29%5E3+%2B+%283y%29%5E3
There is an identity that says
%28a%5E3+%2B+b%5E3%29+=+%28a%2Bb%29%28a%5E2%2Bb%5E2-ab%29 which is factorised completely,
Hence, our a is 2x and our b is 3y. Therefore we get
%282x%2B3y%29%28%282x%29%5E2+%2B+%283y%29%5E2+-+6xy%29
cheers
jon.