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(a2-3a+2除以1)+(a2-5a+6除以1)+(a2-7a+12除以1)=

题目详情
(a2-3a+2除以1)+(a2-5a+6除以1)+(a2-7a+12除以1)=
▼优质解答
答案和解析
(a2-3a+2除以1)+(a2-5a+6除以1)+(a2-7a+12除以1)
= (1/(a2-3a+2))+(1/(a2-5a+6))+(1/(a2-7a+12))
= 1/(a-2)(a-1)+1/(a-2)(a-3)+1/(a-3)(a-4)
=((a-4)(a-3)+(a-1)(a-4)+(a-1)(a-2))/((a-1)(a-2)(a-3)(a-4))
=(3a*a-15a+18)/((a-1)(a-2)(a-3)(a-4))
=(3*(a-2)(a-3))/((a-1)(a-2)(a-3)(a-4))
=3/((a-1)(a-4))