题目内容
解方程.
(1)x-
=
(2)x+
=
(3)3.5x+1.5x=4
(4)
-x=
.
(1)x-
| 5 |
| 8 |
| 3 |
| 4 |
(2)x+
| 3 |
| 4 |
| 7 |
| 8 |
(3)3.5x+1.5x=4
(4)
| 2 |
| 5 |
| 5 |
| 18 |
分析:(1)依据等式的性质,方程两边同时加上
求解,
(2)依据等式的性质,方程两边同时减去
求解,
(3)先化简得5x=4,依据等式的性质,方程两边同时除以5求解.
(3)依据等式的性质,方程两边同时加上x,再同时减去
求解.
| 5 |
| 8 |
(2)依据等式的性质,方程两边同时减去
| 3 |
| 4 |
(3)先化简得5x=4,依据等式的性质,方程两边同时除以5求解.
(3)依据等式的性质,方程两边同时加上x,再同时减去
| 5 |
| 18 |
解答:解:(1)x-
=
,
x-
+
=
+
,
x=
;
(2)x+
=
,
x+
-
=
-
,
x=
;
(3)3.5x+1.5x=4
5x=4,
5x÷5=4÷5,
x=0.8;
(4)
-x=
,
-x+x=
+x,
+x-
=
-
,
x=
.
| 5 |
| 8 |
| 3 |
| 4 |
x-
| 5 |
| 8 |
| 5 |
| 8 |
| 3 |
| 4 |
| 5 |
| 8 |
x=
| 11 |
| 8 |
(2)x+
| 3 |
| 4 |
| 7 |
| 8 |
x+
| 3 |
| 4 |
| 3 |
| 4 |
| 7 |
| 8 |
| 3 |
| 4 |
x=
| 1 |
| 8 |
(3)3.5x+1.5x=4
5x=4,
5x÷5=4÷5,
x=0.8;
(4)
| 2 |
| 5 |
| 5 |
| 18 |
| 2 |
| 5 |
| 5 |
| 18 |
| 5 |
| 18 |
| 5 |
| 18 |
| 2 |
| 5 |
| 5 |
| 18 |
x=
| 11 |
| 90 |
点评:等式的性质是解方程的依据,解方程时注意对齐等号.
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