已知a=5,求(a-4)/(a²-9)÷1/(a-3)*(a²+6a+9)/(a²-8a+16)
问题描述:
已知a=5,求(a-4)/(a²-9)÷1/(a-3)*(a²+6a+9)/(a²-8a+16)
答
(a-4)/(a²-9)÷1/(a-3)*(a²+6a+9)/(a²-8a+16)
=(a-4)/[(a+3)(a-3)]×(a-3)×(a+3)²/(a-4)²
=(a+3)/(a-4)
=8