运用乘法公式计算1:(x+y+2z)(x-y-2z)2:(x+2y-z)²

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运用乘法公式计算1:(x+y+2z)(x-y-2z)2:(x+2y-z)²
运用乘法公式计算
1:(x+y+2z)(x-y-2z)
2:(x+2y-z)²

运用乘法公式计算1:(x+y+2z)(x-y-2z)2:(x+2y-z)²
①(x+y+2z)(x-y-2z)
=[x+(y+2z)][x-(y+2z)]
=x²-(y+2z)²
=x²-y²-4yz-4z²
②(x+2y-z)²=x²+4y²+z²+4xy-2xz-4yz

1:(x+(y+z))*(x-(y-z))平方差
2:将x+2y当作整体,用完全平方公式

1:(x+y+2z)(x-y-2z)
= (x+(y+2z))(x-(y+2z))
= x² - (y +2z)²
= x² - y² -4yz -z²
2:(x+2y-z)²
=x²+4y²+z²+4xy-2xz-4yz