先化简,再求值(3a/a-1 -a/a+1)(a2-1/a),其中a=根号2-2

问题描述:

先化简,再求值(3a/a-1 -a/a+1)(a2-1/a),其中a=根号2-2

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