1.3ab分之a²-4b²×a-2b分之ab=(a+2b)(a-2b)/3ab ×ab/(a-2b)=(a+2b)/3 2.a²-4a+4分之a-1÷a²-4分之a平方-1=(a-1)/(a-2)² ×(a+2)(a-2)/(a+1)(a-1)=(a+2)/(a-2)(a+1) 3.a²+ab分之a-b÷...