Question

(x-3/x-2)/(x+2-(5/(x-2))化简,其中x=4,得

看清楚括号。。。

Answer 1

解：
原式=[(x-3)/(x-2)]÷{x+2-[5/(x-2)]}
=[(x-3)/(x-2)]÷[(x+2)(x-2)/(x-2)-5/(x-2)]
=[(x-3)/(x-2)]÷[(x²-4-5)/(x-2)]
=[(x-3)/(x-2)]÷[(x²-9)/(x-2)]
=[(x-3)/(x-2)]÷[(x+3)(x-3)/(x-2)]
=[(x-3)/(x-2)]×{(x-2)/[(x+3)(x-3)]}
=1/(x+3)
=1/(4+3)
=1/7

Answer 2

答案是1/7，直接带进去算最简单

Answer 3

(x-3/x-2)/[x+2-5/(x-2)]
=(x-3)/(x-2)/[(x²-4-5)]
=(x-3)/(x-2)/(x-3)(x+3)
=1/(x-2)(x+3) x=4
=1/(4-2)(4+3)
=1/14

Answer 4

（x－3/x－2）/【（x＋2）－5/(x－2)】
＝(x－3/x－2)/｛【(x＋2)(x－2)－5】/x－2｝
＝(x－3)/(x－2)/【(x²－9)/x－2】
＝(x－3)/(x－2)×【(x－2)/(x＋3)(x－3)】
＝1/(x＋3)
∵x＝4
∴原式＝1/(4＋3)＝1/7