分析:(1)先根据比例的性质改写成
X=
×15,再根据等式的性质,两边同乘6即可;
(2)根据等式的性质,两边同加上
X,得
+
X=1,两边同减去
,再同乘
即可;
(3)根据等式的性质,两边同除以
,再同乘
即可.
| 1 |
| 6 |
| 4 |
| 9 |
(2)根据等式的性质,两边同加上
| 3 |
| 4 |
| 3 |
| 5 |
| 3 |
| 4 |
| 3 |
| 5 |
| 4 |
| 3 |
(3)根据等式的性质,两边同除以
| 4 |
| 5 |
| 5 |
| 8 |
解答:解:(1)
:
=X:15,
X=
×15,
X×6=
×15×6,
X=40;
(2)1-
X=
,
1-
X+
X=
+
X,
+
X=1,
+
X-
=1-
,
X=
,
X×
=
×
,
X=
;
(3)X÷
×
=1,
X÷
×
÷
=1÷
,
X÷
=
,
X÷
×
=
×
,
X=
.
| 4 |
| 9 |
| 1 |
| 6 |
| 1 |
| 6 |
| 4 |
| 9 |
| 1 |
| 6 |
| 4 |
| 9 |
X=40;
(2)1-
| 3 |
| 4 |
| 3 |
| 5 |
1-
| 3 |
| 4 |
| 3 |
| 4 |
| 3 |
| 5 |
| 3 |
| 4 |
| 3 |
| 5 |
| 3 |
| 4 |
| 3 |
| 5 |
| 3 |
| 4 |
| 3 |
| 5 |
| 3 |
| 5 |
| 3 |
| 4 |
| 2 |
| 5 |
| 3 |
| 4 |
| 4 |
| 3 |
| 2 |
| 5 |
| 4 |
| 3 |
X=
| 8 |
| 15 |
(3)X÷
| 5 |
| 8 |
| 4 |
| 5 |
X÷
| 5 |
| 8 |
| 4 |
| 5 |
| 4 |
| 5 |
| 4 |
| 5 |
X÷
| 5 |
| 8 |
| 5 |
| 4 |
X÷
| 5 |
| 8 |
| 5 |
| 8 |
| 5 |
| 4 |
| 5 |
| 8 |
X=
| 25 |
| 32 |
点评:此题考查了运用等式的性质解方程,即等式两边同加上或同减去、同乘上或同除以一个数(0除外),两边仍相等,同时注意“=”上下要对齐.

