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