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©2026 数学クラブ http://sugaku.club/
月 日（ ）
● 次の方程式を解きなさい
[212-00]
(1)
2
x
＋
4
x
＋
3
=
0
(2)
2
x
−
x
−
12
=
0
(3)
2
x
＋
12
x
＋
32
=
0
(4)
2
x
＋
4
x
−
60
=
0
(5)
2
x
＋
6
x
＋
5
=
0
(6)
2
x
＋
9
x
＋
20
=
0
(7)
2
x
＋
2
x
−
3
=
0
(8)
2
x
−
9
x
＋
14
=
0
(9)
2
x
＋
5
x
−
36
=
0
(10)
2
x
＋
9
x
＋
20
=
0
©2026 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
x
＋
4
x
＋
3
=
0
2
x
＋
4
x
＋
4
−
4
＋
3
=
0
2
(
x
＋
2
)
=
1
x
＋
2
=
±
1
x
=
−3
，
−1
(2)
2
x
−
x
−
12
=
0
2
1
1
x
−
x
＋
−
−
12
4
4
=
0
1
2
(
x
−
)
2
49
=
4
1
x
−
2
7
=
±
2
x
=
4
，
−3
(3)
2
x
＋
12
x
＋
32
=
0
2
x
＋
12
x
＋
36
−
36
＋
32
=
0
2
(
x
＋
6
)
=
4
x
＋
6
=
±
2
x
=
−4
，
−8
(4)
2
x
＋
4
x
−
60
=
0
2
x
＋
4
x
＋
4
−
4
−
60
=
0
2
(
x
＋
2
)
=
64
x
＋
2
=
±
8
x
=
6
，
−10
(5)
2
x
＋
6
x
＋
5
=
0
2
x
＋
6
x
＋
9
−
9
＋
5
=
0
2
(
x
＋
3
)
=
4
x
＋
3
=
±
2
x
=
−1
，
−5
(6)
2
x
＋
9
x
＋
20
=
0
2
81
81
x
＋
9
x
＋
−
＋
20
4
4
=
0
9
2
(
x
＋
)
2
1
=
4
9
x
＋
2
1
=
±
2
x
=
−5
，
−4
(7)
2
x
＋
2
x
−
3
=
0
2
x
＋
2
x
＋
1
−
1
−
3
=
0
2
(
x
＋
1
)
=
4
x
＋
1
=
±
2
x
=
1
，
−3
(8)
2
x
−
9
x
＋
14
=
0
2
81
81
x
−
9
x
＋
−
＋
14
4
4
=
0
9
2
(
x
−
)
2
25
=
4
9
x
−
2
5
=
±
2
x
=
2
，
7
(9)
2
x
＋
5
x
−
36
=
0
2
25
25
x
＋
5
x
＋
−
−
36
4
4
=
0
5
2
(
x
＋
)
2
169
=
4
5
x
＋
2
13
=
±
2
x
=
−9
，
4
(10)
2
x
＋
9
x
＋
20
=
0
2
81
81
x
＋
9
x
＋
−
＋
20
4
4
=
0
9
2
(
x
＋
)
2
1
=
4
9
x
＋
2
1
=
±
2
x
=
−4
，
−5