a)\(\left(2x^2+4x^2\right)+\left[\left(-5xy\right)+xy\right]+\left(3y^2-2y^2\right)=6x^2-4xy+y^2\)
b)\(2x^2-5xy+3y^2+4x^2+xy-2y^2+2x^2+4xy-5y^2\)
=\(\left(2x^2+4x^2+2x^2\right)+\left(-5xy+xy+4xy\right)+\left(3y^2-2y^2-5y^2\right)\)
=\(8x^2-4y^2\)
cảm ơn bạn nhiều
a)2x2-5xy+3y2+4x2+xy-2y2
=\(\left(2x^2+4x^2\right)+\left(-5xy+xy\right)+\left(3y^2-2y^2\right)\)
\(=6x^2-4xy+y^2\)
b)2x2 - 5xy+3y2+4x2+xy-2y2+2x2+4xy-5y2
\(=\left(2x^2+4x^2+2x^2\right)+\left(3y^2-2y^2-5y^2\right)+\left(5xy+xy+4xy\right)\)
\(=8x^2-4y^2+10xy\)