来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/06/16 00:45:38
解方程
7x-3.4x=0.72;
3(x+2.1)=10.5;
3x+3×6.5=31.2.
(1)7x-3.4x=0.72
3.6x=0.72
3.6x÷3.6=0.72÷3.6
x=0.2;
(2)3(x+2.1)=10.5
3(x+2.1)÷3=10.5÷3
x+2.1=3.5
x+2.1-2.1=3.5-2.1
x=1.4;
(3)3x+3×6.5=31.2
3x+19.5=31.2
3x+19.5-19.5=31.2-19.5
3x=11.7
3x÷3=11.7÷3
x=3.9.