题目内容
解方程.
|
1-
|
(x-
|
分析:(1)原式变为0.7x=17.5,根据等式的性质,两边同除以0.7即可;
(2)原式变为
-
x=
,根据等式的性质,两边同
x,得
+
x=
,两边同减去
,再同乘
即可;
(3)根据等式的性质,两边同除以
,得x-
=
,两边同加上
即可.
(2)原式变为
4 |
5 |
4 |
5 |
1 |
2 |
4 |
5 |
1 |
2 |
4 |
5 |
4 |
5 |
1 |
2 |
5 |
4 |
(3)根据等式的性质,两边同除以
5 |
7 |
2 |
3 |
21 |
40 |
2 |
3 |
解答:解:(1)
x-5%x=17.5
0.75x-0.05x=17.5
0.7x=17.5
0.7x÷0.7=17.5÷0.7
x=25;
(2)1-
x-
=
-
x=
-
x+
x=
+
x
+
x=
+
x-
=
-
x=
x×
=
×
x=
;
(3)(x-
)×
=
(x-
)×
÷
=
÷
x-
=
x-
+
=
+
x=
.
3 |
4 |
0.75x-0.05x=17.5
0.7x=17.5
0.7x÷0.7=17.5÷0.7
x=25;
(2)1-
4 |
5 |
1 |
5 |
1 |
2 |
4 |
5 |
4 |
5 |
1 |
2 |
4 |
5 |
4 |
5 |
4 |
5 |
1 |
2 |
4 |
5 |
1 |
2 |
4 |
5 |
4 |
5 |
1 |
2 |
4 |
5 |
1 |
2 |
4 |
5 |
1 |
2 |
4 |
5 |
3 |
10 |
4 |
5 |
5 |
4 |
3 |
10 |
5 |
4 |
x=
3 |
8 |
(3)(x-
2 |
3 |
5 |
7 |
3 |
8 |
(x-
2 |
3 |
5 |
7 |
5 |
7 |
3 |
8 |
5 |
7 |
x-
2 |
3 |
21 |
40 |
x-
2 |
3 |
2 |
3 |
21 |
40 |
2 |
3 |
x=
143 |
120 |
点评:此题考查了根据等式的性质解方程,即等式两边同加上、同减去、同乘上或同除以一个不为0的数,等式仍相等.同时注意“=”上下要对齐.
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