X-2Y=1 x^2-xy-2y^2=7 联立
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X-2Y=1 x^2-xy-2y^2=7 联立
X-2Y=1 x^2-xy-2y^2=7 联立
X-2Y=1 x^2-xy-2y^2=7 联立
由X-2Y=1得X=2y+1代入第二个方程得到:
(2y+1)^2-(2y+1)y-2y^2=3y+1=7
解得y=2 由此x=5
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