已知A=2a+3,B=-4a²+3a-1,C=3a²-4a+4,求4A+{2B-(3B-2C)+6B]+3C}的值

2025-02-26 23:33:46
推荐回答(3个)
回答1:

解:4A+{2B-[(3B-2C)+6B]+3C}
=4A+[2B-(3B-2C+6B)+3C]
=4A+(2B-3B+2C-6B+3C)
=4A+2B-3B+2C-6B+3C
=4A-7B+5C
把A=2a+3,B=-4a²+3a-1,C=3a²-4a+4代入上式,得:
4(2a+3)-7(-4a²+3a-1)+5(3a²-4a+4)
=8a+12+28a²-21a+7+15a²-20a+20
=43a²-33a+39

回答2:

那个中括号那呢

回答3:

。。