SOLUTION: (6x^2-7xy+y^2)+(-9x^2-9xy-y^2)+(x^2+xy-4y^2)

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Question 529381: (6x^2-7xy+y^2)+(-9x^2-9xy-y^2)+(x^2+xy-4y^2)
Answer by Maths68(1474) About Me  (Show Source):
You can put this solution on YOUR website!
=%286x%5E2-7xy%2By%5E2%29%2B%28-9x%5E2-9xy-y%5E2%29%2B%28x%5E2%2Bxy-4y%5E2%29
=6x%5E2-7xy%2By%5E2-9x%5E2-9xy-y%5E2%2Bx%5E2%2Bxy-4y%5E2%29
=6x%5E2%2Bx%5E2-9x%5E2%2By%5E2-y%5E2-4y%5E2-9xy-7xy%2Bxy%29 [Combine like terms]
=7x%5E2-9x%5E2%2Bcross%28y%5E2%29-cross%28y%5E2%29-4y%5E2-16xy%2Bxy%29
=-2x%5E2-4y%5E2-15xy%29
=-%282x%5E2%2B4y%5E2%2B15xy%29