
已知2x²-2x-3=0,求代数式x²-1分之(x-1)²+ x+1分之2x²-x的值?跪求啊!急需
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∵2x²-2x-3=0,
∴2x²-1=2x+2=2(x+1)
∴(x-1)²/(x²-1)+ (2x²-x)/(x+1)
=(x-1)²/[(x-1)(x+1)]+(2x²-x)/(x+1)
=(x-1)/(x+1)+(2x²-x)/(x+1)
=(2x²-1)/(x+1)
=2(x+1)/(x+1)
=2
∴2x²-1=2x+2=2(x+1)
∴(x-1)²/(x²-1)+ (2x²-x)/(x+1)
=(x-1)²/[(x-1)(x+1)]+(2x²-x)/(x+1)
=(x-1)/(x+1)+(2x²-x)/(x+1)
=(2x²-1)/(x+1)
=2(x+1)/(x+1)
=2
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