SOLUTION: Please help me factor out 81y^4 + 64z^4!!

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Question 889302: Please help me factor out 81y^4 + 64z^4!!
Answer by Nigelyul(18) About Me  (Show Source):
You can put this solution on YOUR website!
To complete the square add 144y%5E2%2Az%5E2 and also subtract it to compensate of the addition.
%2881y%5E4+%2B+64z%5E4%29+%2B+%28144y%5E2%2Az%5E2+-+144y%5E2%2Az%5E2%29
%2881%5E4+%2B+144y%5E2%2Az%5E2+%2B+64z%5E4%29+-+144y%5E2%2Az%5E2
%289y%5E2+%2B+8z%5E2%29%5E2+-+144y%5E2%2Az%5E2
Now it's a difference of two squares
%289y%5E2+%2B+12yz+%2B+8z%5E2%29%289y%5E2+-+12yz+%2B+8z%5E2%29