SOLUTION: 16x^2+72xy+81y^2 facotor each plynomial completely

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Question 26071: 16x^2+72xy+81y^2
facotor each plynomial completely
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Notice that the first term16x%5E2 and the last term81y%5E2 are both perfect squares: %284x%29%5E2 and %289y%29%5E2 respectivley. This would suggest trying the following:
%284x+%2B+9y%29%284x+%2B+9y%29 as the factors.
Check using FOIL.
%284x+%2B+9y%29%284x+%2B+9y%29+=+16x%5E2+%2B+36xy+%2B+36xy+%2B+81y%5E2 = 16x%5E2+%2B+72xy+%2B+81y%5E2
The factors are: %284x+%2B+9y%29%284x+%2B+9y%29+=+%284x+%2B+9y%29%5E2