已知a与-2b互为相反数,b与3c互为相反数,试求1/4a+1/2b+3c+3/2的值

分类: 作业答案 • 2022-02-14 15:23:37

问题描述：

答

a-2b=0
b+3c=0
原式=1/4a+1/2b+3c+3/2
=1/4·2b+1/2·b+3c+3/2
=1/2·b+1/2·b+3c+3/2
=b+3c+3/2
=0+3/2
=3/2

答

a与-2b互为相反数,则a-2b=0
b与3c互为相反数,则b+3c=0
于是
1/4a+1/2b+3c+3/2
=1/4a-1/2b+b+3c+3/2
=1/4*(a-2b)+(b+3c)+3/2
=1/4*0+0+3/2
=3/2