题目内容
求未知数x.
=
6×3-1.8x=7.2
x-
x=9.45.
| 10 |
| x |
| 2.5 |
| 0.8 |
6×3-1.8x=7.2
x-
| 1 |
| 8 |
(1)
=
,
2.5x=10×0.8,
2.5x÷2.5=8÷2.5,
x=3.2;
(2)6×3-1.8x=7.2,
18-1.8x=7.2,
18-1.8x+1.8x=7.2+1.8x,
18=7.2+1.8x,
18-7.2=7.2+1.8x-7.2,
10.8=1.8x,
10.8÷1.8=1.8x÷1.8,
x=6;
(3)x-
x=9.45,
x=9.45,
x÷
=9.45÷
,
x=10.8.
| 10 |
| x |
| 2.5 |
| 0.8 |
2.5x=10×0.8,
2.5x÷2.5=8÷2.5,
x=3.2;
(2)6×3-1.8x=7.2,
18-1.8x=7.2,
18-1.8x+1.8x=7.2+1.8x,
18=7.2+1.8x,
18-7.2=7.2+1.8x-7.2,
10.8=1.8x,
10.8÷1.8=1.8x÷1.8,
x=6;
(3)x-
| 1 |
| 8 |
| 7 |
| 8 |
| 7 |
| 8 |
| 7 |
| 8 |
| 7 |
| 8 |
x=10.8.
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