题目内容
求未知数.
| 0.75X+3×0.8=7.5 |
|
|
(l)
x-5=10,
x-5+5=10+5,
x=15,
x÷
=15÷
,
x=25;
(2)0.75x+3×0.8=7.5,
0.75x+2.4=7.5,
0.75x+2.4-2.4=7.5-2.4,
0.75x=5.1,
0.75x÷0.75=5.1÷0.75,
x=6.8;
(3)
=
,
2.5x=7.5×12,
2.5x÷2.5=7.5×12÷2.5,
x=36;
(4)
=8:
,
x=4×8,
x=32,
x÷
=32÷
,
x=64.
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 5 |
x=25;
(2)0.75x+3×0.8=7.5,
0.75x+2.4=7.5,
0.75x+2.4-2.4=7.5-2.4,
0.75x=5.1,
0.75x÷0.75=5.1÷0.75,
x=6.8;
(3)
| 7.5 |
| x |
| 2.5 |
| 12 |
2.5x=7.5×12,
2.5x÷2.5=7.5×12÷2.5,
x=36;
(4)
| x |
| 4 |
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 2 |
| 1 |
| 2 |
x=64.
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