1、（1）计算{(3-x)⼀(x-2)}⼀(x-2-(13-4x)⼀(x-2)) (2) {1+4⼀(a-2)(a-4+4⼀a)-3}⼀(1⼀a눀-1)

　(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)

(1）{(3-x)/(x-2)}/(x-2-(13-4x)/(x-2))
={(3-x)/(x-2)}/(((x-2)^2-(13-4x))/(x-2))
=(3-x)/((x-2)^2-13+4x)
=(3-x)/(x^2-4x+4-13+4x)
=(3-x)/(x^2-9)
=(3-x)/((x+3)(x-3))
=-1/(x+3)