已知A=-xy+yz+xz,B=-2xy+yz-xz 求下列式子的代数和 (1) A+B (2) 3A-2B 过程加讲解

2025-06-26 04:33:10
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回答1:

(1) A+B
=(-xy+yz+xz)+(-2xy+yz-xz)
=-xy+yz+xz-2xy+yz-xz
=-3xy+2yz

(2) 3A-2B
=3(-xy+yz+xz)-2(-2xy+yz-xz)
=-3xy+3yz+3xz+4xy-2yz+2xz
=xy+yz+5xz