(ab-3/2b-1/2)-(ab-3/2a+1)化简后是多少?当a等于1时,b等于2是,求值

a^2-3ab+b^2/ab=( )/ab-3 a^2-3ab+b^2/ab=( )/ab -3 (a+b)^2- 2b-1 绝对值=0 求证ab-[2ab-3(ab-1)] 已知ab^2=-1,求-ab（a^2b^5-ab^3-b)的值 -1/2ab^2(b^2+3ab^2)计算 (-3ab)(a^2b-3ab^2+1) 3a²b-[2ab²-6(ab-1/2a²b)+4ab]-2ab a^2b-ab+2ab^2-5a^b-4ab+3ab^2化简快 已知a+b=1/2,ab=3/b求ab+2ab+ab的值 3ab{(-2ab)平方-3b(ab-a平方b)+ab平方}算出来多少Rt ab^3+b^2+b-a+1 计算：2ab[(2ab)²-3b(ab+a²b)-ab²] 已知（a-2）+（b+1）=0,求多项式3ab+ab-3ab+5ab+ab+2分之1ab (-1/2ab)(2/3ab^2-2ab+4/3b) (-1/2ab)(2/3ab^2+2ab-4/3b) 化简(3/4ab+3ab-2/3b)(1/2ab) 计算3ab(2ab^2-ab-b^2)-6ab(a^2-2ab-b^2) (a^2b-ab-a+1)/(ab^2+3ab-b-3)÷(a^2+a_2)/(b^2+b-6)