问题标题：
【1、（1）计算{(3-x)/(x-2)}/(x-2-(13-4x)/(x-2))(2){1+4/(a-2)(a-4+4/a)-3}/(1/a²-1)】
问题描述：
1、（1）计算{(3-x)/(x-2)}/(x-2-(13-4x)/(x-2))(2){1+4/(a-2)(a-4+4/a)-3}/(1/a²-1)
柏国柱回答：
(1){(3-x)/(x-2)}/(x-2-(13-4x)/(x-2))
={(3-x)/(x-2)}/{(x-2)*(x-2)-(13-4x)/(x-2)
={(3-x)/(x-2)}/{((x²-4x+4)-(13-4x))/(x-2}
={(3-x)/(x-2)}/{(x²-4x+4-13+4x)/(x-2}
={(3-x)/(x-2)}/{(x²-9)/(x-2)}
={(3-x)/(x-2)}/{(x-3)*(x+3)/(x-2)}
=(3-x)/(x-2)*(x-2)/(x-3)/(x+3)
=-(x-3)/(x-3)/(x+3)
=-1/(x+3)
(2){1+4/(a-2)(a-4+4/a)-3}/(1/a²-1)
={1+4/(a-2)((a-2)-2/a(a-2))-3}/{(1/a-1)(1/a+1)}
=(1+4-2/a-3)/{(1/a-1)(1/a+1)}
=(2-2/a)/{(1/a-1)(1/a+1)}
=2(1-1/a)/{-(1-1/a)(1/a+1)}
=-2/(1/a+1)
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