Question

tính (x-y)(2x+y+z)-(x-y)(x+z)+(y^2-x^2)

Answer 1

\(\left(x-y\right)\left(2x+y+z\right)-\left(x-y\right)\left(x+z\right)+\left(y^2-x^2\right)=\left(x-y\right)\left(2x+y+z-x-z-x-y\right)=0\)