题目内容
解方程.
| 0.36×5-2X=0.4 | 2X+3X=20.5. |
(1)
=
,
0.7x=3.5×0.5,
0.7x÷0.7=1.75÷0.7,
x=2.5;
(2)0.36×5-2X=0.4,
1.8-2X=0.4,
1.8-2X+2X=0.4+2X,
0.4+2X=1.8,
0.4+2X-0.4=1.8-0.4,
2X=1.4,
2X÷2=1.4÷2,
X=0.7;
(3)2X+3X=20.5,
5X=20.5,
5X÷5=20.5÷5,
X=4.1.
| 3.5 |
| 0.7 |
| x |
| 0.5 |
0.7x=3.5×0.5,
0.7x÷0.7=1.75÷0.7,
x=2.5;
(2)0.36×5-2X=0.4,
1.8-2X=0.4,
1.8-2X+2X=0.4+2X,
0.4+2X=1.8,
0.4+2X-0.4=1.8-0.4,
2X=1.4,
2X÷2=1.4÷2,
X=0.7;
(3)2X+3X=20.5,
5X=20.5,
5X÷5=20.5÷5,
X=4.1.
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