已知x2+y2-10x-6y+34=0,求(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy 的值.
问题描述:
已知x2+y2-10x-6y+34=0,求(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy 的值.
答
x2+y2-10x-6y+34=0
x²-10x+25+y²-6y+9=0
(x-5)²+(y-3)²=0
∴x=5 y=3
(x-y/x+y)2÷x2-y2/xy×x2+2xy+y2/x2-xy
=(x-y)²/(x+y)²×xy/(x+y)(x-y)×(x+y)²/x(x-y)
=y/(x+y)
=3/(5+3)
=3/8
答
你好
x²+y²-10x-6y+34=0
(x-5)²+(y-3)²=0
每项都大于等于0,只有等于0时上式才成立,所以
x=5
y=3
(x-y/x+y)²÷(x²-y²)/xy×(x²+2xy+y²)/(x²-xy)
=(x-y)²/(x+y)²×xy/[(x-y)(x+y)]×(x+y)²/x(x-y)
=y/(x+y)
=3/8
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