9x+3x=3.6 9x-3x=3.6
问题描述：
9x+3x=3.6 9x-3x=3.6
答
9x+3x=3.6
12x=3.6
x=3.6/12
x=0.3
9x-3x=3.6
6x=3.6
x=3.6/6
x=0.6