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©2024 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
＋
5
x
＋
4
=
0
(2)
2
x
＋
x
−
12
=
0
(3)
2
x
−
8
x
＋
12
=
0
(4)
2
x
＋
8
x
−
9
=
0
(5)
2
x
＋
6
x
−
40
=
0
(6)
2
x
＋
4
x
＋
3
=
0
(7)
2
x
−
5
x
＋
6
=
0
(8)
2
x
＋
10
x
＋
24
=
0
(9)
2
x
−
15
x
＋
54
=
0
(10)
2
x
＋
3
x
−
28
=
0
©2024 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
x
＋
5
x
＋
4
=
0
2
25
25
x
＋
5
x
＋
−
＋
4
4
4
=
0
5
2
(
x
＋
)
2
9
=
4
5
x
＋
2
3
=
±
2
x
=
−4
，
−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
=
3
，
−4
(3)
2
x
−
8
x
＋
12
=
0
2
x
−
8
x
＋
16
−
16
＋
12
=
0
2
(
x
−
4
)
=
4
x
−
4
=
±
2
x
=
6
，
2
(4)
2
x
＋
8
x
−
9
=
0
2
x
＋
8
x
＋
16
−
16
−
9
=
0
2
(
x
＋
4
)
=
25
x
＋
4
=
±
5
x
=
−9
，
1
(5)
2
x
＋
6
x
−
40
=
0
2
x
＋
6
x
＋
9
−
9
−
40
=
0
2
(
x
＋
3
)
=
49
x
＋
3
=
±
7
x
=
4
，
−10
(6)
2
x
＋
4
x
＋
3
=
0
2
x
＋
4
x
＋
4
−
4
＋
3
=
0
2
(
x
＋
2
)
=
1
x
＋
2
=
±
1
x
=
−1
，
−3
(7)
2
x
−
5
x
＋
6
=
0
2
25
25
x
−
5
x
＋
−
＋
6
4
4
=
0
5
2
(
x
−
)
2
1
=
4
5
x
−
2
1
=
±
2
x
=
3
，
2
(8)
2
x
＋
10
x
＋
24
=
0
2
x
＋
10
x
＋
25
−
25
＋
24
=
0
2
(
x
＋
5
)
=
1
x
＋
5
=
±
1
x
=
−4
，
−6
(9)
2
x
−
15
x
＋
54
=
0
2
225
225
x
−
15
x
＋
−
＋
54
4
4
=
0
15
2
(
x
−
)
2
9
=
4
15
x
−
2
3
=
±
2
x
=
6
，
9
(10)
2
x
＋
3
x
−
28
=
0
2
9
9
x
＋
3
x
＋
−
−
28
4
4
=
0
3
2
(
x
＋
)
2
121
=
4
3
x
＋
2
11
=
±
2
x
=
−7
，
4