解2r+3.14*r=15.42
问题描述：
解2r+3.14*r=15.42
答
2r+3.14*r=15.42
5.14r = 15.42
r = 15.42/5.14
r = 3
答
r=3
答
2r+3.14*r=15.42
5.14r = 15.42
r = 3
答
5.14*r=15.42；
r=15.42/5.14
r=3;