若x²+xy-2y²=0 (x²+3xy+y²)/(x²+y²)=what
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若x²+xy-2y²=0(x²+3xy+y²)/(x²+y²)=what若x²+xy-2y²=0(x²+3xy
若x²+xy-2y²=0 (x²+3xy+y²)/(x²+y²)=what
若x²+xy-2y²=0 (x²+3xy+y²)/(x²+y²)=what
若x²+xy-2y²=0 (x²+3xy+y²)/(x²+y²)=what
x²+xy-2y²=0,两边同时除以y²,可以得到(x/y)²+x/y-2=0,求解得x/y=1或-2,同理,对(x²+3xy+y²)/(x²+y²)上下同时除以y²,计算结果为5/2或者-1/5
x²+xy-2y²=0
(x-y)(x+2y)=0
x-y=0或x+2y=0
x=y或x=-2y
(1)x=y时,则
(x²+3xy+y²)/(x²+y²)
=(y²+3y²+y²)/(y²+y²)
=5y²/2y...
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x²+xy-2y²=0
(x-y)(x+2y)=0
x-y=0或x+2y=0
x=y或x=-2y
(1)x=y时,则
(x²+3xy+y²)/(x²+y²)
=(y²+3y²+y²)/(y²+y²)
=5y²/2y²
=5/2
(2)x=-2y时,则
(x²+3xy+y²)/(x²+y²)
=(4y²-6y²+y²)/(4y²+y²)
=-y²/5y²
=-1/5
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