3b-2c-[-4a+(c+3b)]+c
问题描述:
3b-2c-[-4a+(c+3b)]+c
答
3b-2c-[-4a+(c+3b)]+c
=3b-2c-(-4a+c+3b)+c
=3b-2c+4a-c-3b+c
=-2c+4a