Rút gọn biểu thức: (x – y + z)^2 + (z – y)^2 + 2(x – y + z)(y – z)
Giải thích
x-y+z2 + z-y2 + 2(x – y + z)(y – z)
= x-y+z2 + 2(x – y + z)(y – z) + y-z2
= x-y+z+y-z2=x2
x-y+z2 + z-y2 + 2(x – y + z)(y – z)
= x-y+z2 + 2(x – y + z)(y – z) + y-z2
= x-y+z+y-z2=x2