3a+【b-4a】-【5-7a】=
问题描述:
3a+【b-4a】-【5-7a】=
答
3a+【b-4a】-【5-7a】
=3a+b-4a-5+7a
=6a+b-5
3a+【b-4a】-【5-7a】=
3a+【b-4a】-【5-7a】
=3a+b-4a-5+7a
=6a+b-5