原式=3a/(a-1)*(a+1)(a-1)/a-a(a+1)*(a+1)(a-1)/a
=3(a+1)-(a-1)
=3a+3-a+1
=2a+4
当a=√2-2 时,原式=2*（√2-2）+4
=2√2
答：所求式的化简结果为2a+4
当a=-2 时,求值结果为2√2 .原式=3a/(a-1)*(a+1)(a-1)/a-a/(a+1)*(a+1)(a-1)/a是这样吗？谢谢是的不客气