已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值x+x/1=3,求(x²)²+x²+1/x²的值
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已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值x+x/1=3,求(x²)²+x²+1/x²的值
已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值
x+x/1=3,求(x²)²+x²+1/x²的值
已知y/X=3,求x²-xy+y²/x²+2xy-3y²的值x+x/1=3,求(x²)²+x²+1/x²的值
应该是x/y=3吧:
∴x=3y,代入原式,
原式=【(3y)²-3y*y+y²】/【(3y)²+2*3y*y-3y²】
=(7y²)/(12x²)
=7/12
(2)∵x+1/x=3
∴x²+1/X²+2=9,
x²+1/X²=7,
(x²)²+x²+1/x²
=x²+1+1/X²
=7+1
=8,
∴x²/[(x²)²+x²+1]=1/8