Question

Answer 1

bạn đăng tách ra nhé 

1, \(=-4x^2y+3xy^2+5\)

2, \(=x^2+7xy-y^2\)

4, \(=x^2-4xy+4y^2=\left(x-2y\right)^2\)

 

Answer 2

6: \(=\left(3x^2+x^2-4x^2\right)+\left(-2xy-xy\right)+\left(y^2+2y^2+y^2\right)=4y^2-3xy\)

7: \(=\left(x^2+y^2-x^2-y^2\right)+\left(-2xy-2xy\right)+4xy-1=-1\)

9: \(=x^2-7y^2-4y^2+5xy+2xy=x^2+7xy-11y^2\)