初二数学 先化简，再求值

Question

初二数学 先化简，再求值需要详细过程，谢谢

Answer 1

示

Answer 2

解：
原式=(a-3)/3a(a-2)÷[(a+2)-5/(a-2)]
=(a-3)/3a(a-2)÷[(a+2)(a-2)/(a-2)-5/(a-2)]
=(a-3)/3a(a-2)÷(a²-9)/(a-2)
=(a-3)/3a(a-2)×(a-2)/(a+3)(a-3)
=1/3a(a+3)
=1/3(a²+3a)
=1/(3×1)
=1/3

Answer 3

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追答