化简求值:1/x+2-x的平方+2X+1/x+2除以x的平方-1/x-1,其中x=根号2-2
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化简求值:1/x+2-x的平方+2X+1/x+2除以x的平方-1/x-1,其中x=根号2-2
化简求值:1/x+2-x的平方+2X+1/x+2除以x的平方-1/x-1,其中x=根号2-2
化简求值:1/x+2-x的平方+2X+1/x+2除以x的平方-1/x-1,其中x=根号2-2
原式=[1/(x+2)]-[(x²+2x+1)/(x+2)]÷[(x²-1)/(x-1)]
=[1/(x+2)]-[(x+1)²/(x+2)]÷[(x+1)(x-1)/(x-1)]
=[1/(x+2)]-[(x+1)²/(x+2)]÷(x+1)
=[1/(x+2)]-[(x+1)²/(x+2)]×[1/(x+1)]
=[1/(x+2)]-[(x+1)/(x+2)]
=(1-x-1)/(x+2)
=-x/(x+2)
当x=√2-2时
原式=-(√2-2)/(√2-2+2)
=(2-√2)/√2
=√2(2-√2)/2
=(2√2-2)/2
=√2-1
x+2分之x-x+2分之x平方+2x+1除以x-1分之x平方-1
=[x/(x+2)-(x²+2x+1)/(x+2)]÷(x²-1)/(x-1)
=[(x-x²-2x-1)/(x+2)]÷(x+1)
=(-x²-x-1)/(x+2)(x+1)
=(-x²-x-1)/(x²+3x+2) 其中x=...
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x+2分之x-x+2分之x平方+2x+1除以x-1分之x平方-1
=[x/(x+2)-(x²+2x+1)/(x+2)]÷(x²-1)/(x-1)
=[(x-x²-2x-1)/(x+2)]÷(x+1)
=(-x²-x-1)/(x+2)(x+1)
=(-x²-x-1)/(x²+3x+2) 其中x=根号3
=[-(√3)²-√3-1)]/[(√3)²+3*√3+2]
=(-4-√3)/(5+3√3)
=(-4-√3)(5-3√3)/(5+3√3)(5-3√3)
=(-20-5√3+12√3+9)/(25-27)
=(-11+7√3)/(-2)
=(11-7√3)/2
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