已知X方-2=0,求代数式(X方-1)方/X方-1 + X方/X+1的值

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x²-2=0x²=2x=±√2原式=(2-1)²/(2-1)+2/(x+1)=1+2/(x+1)=(x+3)/(x+1)=(x+3)(x-1)/(x+1)(x-1)=(x²+2x-3)/(x²-1)=(2+2x-3)/(2-1)=2x-1=2√2-1或-2√2-1
======以下答案可供参考======
供参考答案1:
两个方程相减
x+y=-2
2x+2y=-4
3x+2y=k+1
x=k+5y=-2-x=-x-7
xk+5-x-7x>-7所以-7