15(x+2.4)+21x=180
问题描述：
15(x+2.4)+21x=180
答
15x+2.4x15+21x=180
36x=180-2.4x15
x=4
答
15(x+2.4)+21x=180
15x+36+21x=180
36x=180-36
36x=144
x=4
答
11
答
15x+36+21x=180
36x=144
x=4
答
15x+15*2.4+21x=180
15x+36+21x=180
15x+21x+36=180
36x+36=180
36x=180-36
36x=144
x=144/36
x=4