Question

Rút gọn BT:

\(a,2\left(x-y\right)\left(x+y\right)+\left(x+y\right)^2+\left(x-y\right)^2\)

\(b,\left(x-y+z\right)^2+\left(z-y\right)^2+2\left(x-y+x\right)\left(y-z\right)\)

Answer 1

\(a,2\left(x-y\right)\left(x+y\right)+\left(x+y\right)^2+\left(x-y\right)^2\)

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

\(=2x^2-2y^2+x^2+2xy+y^2+x^2-2xy+y^2\)

\(=4x^2\)

Answer 2

a,2(x-y)(x+y)+(x+y)²+(x-y)²

=2(x²-y²)+x²+2xy+y²+x²-2xy+y²

=4x²

b,=x²

Answer 3

khỏi viết đề nhs

A/2(x² -y² )+x² +2xy+y² +x² -2xy+y²

= 2x ²-2y² +x ²+2xy+y²+x²-2xy+y² 

=4x² 

B/x² -y² +z² +z² -2zy+y² +2x-2y+2z+2y-2z+xy-xz-y² +yz+xy-xz

=mấy bạn tự rút gọn nhé ! k giùm lun

Answer 4

a) \(\left(x+y\right)^2+2\left(x-y\right)\left(x+y\right)+\left(x-y\right)^2=\left[\left(x+y\right)+\left(x-y\right)\right]^2=\left(2x\right)^2=4x^2\)

b) \(\left(x-y+z\right)^2+\left(z-y\right)^2+2\left(x-y+z\right)\left(y-z\right)=\left[\left(x-y+z\right)+\left(y-z\right)\right]^2=x^2\)