1.(a+b/ab)-(b/ab-a^2)=a+b/ab-b/ab+a^2=a+a^2
2.(1/a-3)+(6/9-a^2)-(a-1/6+2a)
*****这个三个括号里面的式子我是按a-[1/(6+2a)]算的
=(1/a-3)-(6/(a+3)(a-3))-(a-1/2(3+a))
=(1/a-3)-[1/(a-3)-1/(a+3)]-(a-1/2(3+a))
=1/(a+3)-a+1/2(3+a)
=3/2(a+3)+a
3.(a^2/a^2-b^2)-(b^2/b^2-a^2)+(2ab/a^2-b^2)
=(a^2+b^2/a^2-b^2)+(2ab/a^2-b^2)
=(a^2+b^2+2ab/a^2-b^2)
=(a+b)^2/(a+b)(a-b)
=(a+b)/(a-b)
建议你下次括号要标准确一点,不然容易把题目弄错了的