简便方法计算 1)99^2+198+1 2)(x+y-z)^2

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简便方法计算 1)99^2+198+1 2)(x+y-z)^2
简便方法计算 1)99^2+198+1 2)(x+y-z)^2

简便方法计算 1)99^2+198+1 2)(x+y-z)^2
99^2+198+1
=99^2+2x1x99+1
=(99+1)²
=100x100
=10000
(x+y-z)^2
=(x+y-z)(x+y-z)
= x²+xy-xz+xy+y²-yz-xz-yz+z²
= x²+2xy-2xz-2yz+y²+z²