ab/a+b=3 a-2ab+b/2a-3ab+2b?

ab/a+b=3 a-2ab+b/2a-3ab+2b? a^2-3ab+b^2/ab=( )/ab-3 a^2-3ab+b^2/ab=( )/ab -3 (a-b)^3+2ab(a-b) a+b/2ab 2AB/A+B a+b/2ab （a+ab)-[(ab-2b)-a]-(-9ab),其中a+b=-7,ab=3. a^3-ab^2 =a （a^2 -b^2) =a(a+b)(a-b) b/a+a/b=3,求2ab/(a*a+b*b)-(3a*a+ab+3b*b)/2ab的值 已知a*a-ab=3,ab+b*b=-5,求代数式a*a+b*b与a*a-2ab-b*b的值 1/4a^2b^2{3ab(a+b)-5a(ab-b^2)}=? 如果a+b=3,ab=-1,那么(a+b)2-a-b+ab=? ab=-2 a+b=3 求ab(a²+b²)-a-b 1/a+1/b=3则a-ab+b/a+2ab+b值是? [(a^2-b^2)/b]^2/(a^2+ab)^3*(ab/b-a)^2另：a^2+ab=9 若a+b=3 ab=-2,求a+ab+ab+b的值 已知3a*a+ab-2b*b=0(a不等于0,b不等于0),求a/b-b/a-(a*a+b*b)/ab的值.