(x-5y)(-x-5y)-(-x+5y)^2
=-(x-5y)(x+5y)-(-x+5y)^2
=-[x²-(5y)²]-(-x+5y)^2
=-x²+25y²-x²-25y²+10xy
=-2x²+10xy
=-2×0.5²+10×0.5×(-1)
=-0.5-5
=-5.5
先化简,再求值:(x-5y)(-x-5y)-(-x+5y)的平方,其中x=0.5,y=-1
先化简,再求值:(x-5y)(-x-5y)-(-x+5y)的平方,其中x=0.5,y=-1
数学人气:288 ℃时间:2020-02-05 00:46:14
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