已知3a=5b+2c,2分之3a+2分之1b=4c 又c≠0(1)求a:b:c(2)求(3a-2b+5c)分之(2a+3b-4c)

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/12 16:58:47
已知3a=5b+2c,2分之3a+2分之1b=4c 又c≠0(1)求a:b:c(2)求(3a-2b+5c)分之(2a+3b-4c)

已知3a=5b+2c,2分之3a+2分之1b=4c 又c≠0(1)求a:b:c(2)求(3a-2b+5c)分之(2a+3b-4c)
已知3a=5b+2c,2分之3a+2分之1b=4c 又c≠0
(1)求a:b:c
(2)求(3a-2b+5c)分之(2a+3b-4c)

已知3a=5b+2c,2分之3a+2分之1b=4c 又c≠0(1)求a:b:c(2)求(3a-2b+5c)分之(2a+3b-4c)
5b+2c=3a
3a/2 + b/2 =4c——3a+b=8c——5b+2c+b=8c——b=c
同理可证:a/b = 7/3
即a:b:c=7:3:3
2a+3b-4c / 3a-2b+5c =3(2a+3b-4c) / 3(3a-2b+5c)=2(5b+2c)+ 9b - 12c /3(5b+2c-2b+5c)=11/30