求(x+2y+3z)(x-2y-3z)
问题描述：
求(x+2y+3z)(x-2y-3z)
答
原式
=(x+2y+3z)[x-(2y+3z)]
=x²-(2y+3z)²
=x²-4y²-12yz-9z²
答
(x+2y+3z)(x-2y-3z)
=(x+2y+3z)[x-(2y+3z)]
=x^2-(2y+3z)^2
=x^2-4y^2-12xy-9z^2
答
(x+2y+3z)(x-2y-3z)
=[x+(2y+3z)][x-(2y+3z)]
=x²-(2y+3z)²
=x²-(4y²+12yz+9z²)
=x²-4y²-12yz-9z²
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