1.求代数式的值:x²-2x/x²-4 ÷ (x-2 - 2x-4/x+2),其中x=3.
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1.求代数式的值:x²-2x/x²-4 ÷ (x-2 - 2x-4/x+2),其中x=3.
1.求代数式的值:x²-2x/x²-4 ÷ (x-2 - 2x-4/x+2),其中x=3.
1.求代数式的值:x²-2x/x²-4 ÷ (x-2 - 2x-4/x+2),其中x=3.
原式=x(x-2)/(x+2)(x-2)÷[(x-2)(x+2)-(2x-4)]/(x+2)
=x/(x+2)÷(x²-4-2x+4)/(x+2)
=x/(x+2)÷(x²-2x)/(x+2)
=x/(x+2)*(x+2)/x(x-2)
=1/(x-2)
=1/(3-2)
=1
=x(x-2)/(x+2)(x-2) ÷[(x-2)(x+2)-(2x-4)]/(x+2)]
=x/(x+2)×(x+2)/x(x-2)
=1/(x-2)
当x=3时
原式=1/(3-2)=1