问题标题:
数学题目.已知:x²-4x+4与丨y-1丨互为相反数,则式子(x/y-y/x)÷(x+y)的值为?化简求值(3x/x+1-x/x-1)÷(x-2)/(x²-1),其中x=根号2/2
问题描述:
数学题目.
已知:x²-4x+4与丨y-1丨互为相反数,则式子(x/y-y/x)÷(x+y)的值为?
化简求值
(3x/x+1-x/x-1)÷(x-2)/(x²-1),其中x=根号2/2
牛立军回答:
x²-4x+4与丨y-1丨互为相反数∴x²-4x+4+丨y-1丨=0(x-2)²+|y-1|=0∴x-2=0y-1=0∴x=2y=1(x/y-y/x)÷(x+y)=(x²-y²)/xy×1/(x+y)=(x-y)/xy当x=2,y=1时原式=(2-1)/2=1/22、原式=3x/(x+1)×(x...
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