计算:(1)y/4x²y-1/12y²;(2)2/x+y-x+3/x+y(3)a²/a+3-9/a+3

问题描述:

计算:(1)y/4x²y-1/12y²;(2)2/x+y-x+3/x+y(3)a²/a+3-9/a+3

1/4x^2-1/12y^2,5/x+2y-x,a-9/a+6