(2a²-4a-6)/(a²+9-6a) =[2(a+1)(a-3)]/(a-3)²=2(a+1)/(a-3)(4a+8)×4+(6+a-a²)/(3a-a²)=16a+32+(3-a)(2+a)/a(3-a)=16a+32+(a+2)/a=33+(16a²+2)/a