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©2025 数学クラブ http://sugaku.club/
月 日（ ）
● 次の方程式を解きなさい
[211-00]
(1)
2
(
x
＋
2
)
=
9
(2)
2
(
x
＋
8
)
−
25
=
0
(3)
2
(
x
＋
5
)
=
8
(4)
2
(
x
−
5
)
=
25
(5)
2
(
x
−
2
)
=
9
(6)
2
(
x
＋
6
)
−
5
=
0
(7)
2
(
x
＋
6
)
=
49
(8)
2
(
x
＋
6
)
=
4
(9)
2
(
x
−
6
)
−
8
=
0
(10)
2
(
x
＋
1
)
=
25
(11)
2
(
x
＋
6
)
=
9
(12)
2
(
x
＋
2
)
−
16
=
0
©2025 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
(
x
＋
2
)
=
9
x
＋
2
=
±
3
x
=
−
2
±
3
x
=
1
，
−5
(2)
2
(
x
＋
8
)
−
25
=
0
x
＋
8
=
±
5
x
=
−
8
±
5
x
=
−3
，
−13
(3)
2
(
x
＋
5
)
=
8
x
＋
5
2
=
±
2
x
2
=
−
5
±
2
(4)
2
(
x
−
5
)
=
25
x
−
5
=
±
5
x
=
5
±
5
x
=
10
，
0
(5)
2
(
x
−
2
)
=
9
x
−
2
=
±
3
x
=
2
±
3
x
=
5
，
−1
(6)
2
(
x
＋
6
)
−
5
=
0
x
＋
6
5
=
±
x
5
=
−
6
±
(7)
2
(
x
＋
6
)
=
49
x
＋
6
=
±
7
x
=
−
6
±
7
x
=
1
，
−13
(8)
2
(
x
＋
6
)
=
4
x
＋
6
=
±
2
x
=
−
6
±
2
x
=
−4
，
−8
(9)
2
(
x
−
6
)
−
8
=
0
x
−
6
2
=
±
2
x
2
=
6
±
2
(10)
2
(
x
＋
1
)
=
25
x
＋
1
=
±
5
x
=
−
1
±
5
x
=
4
，
−6
(11)
2
(
x
＋
6
)
=
9
x
＋
6
=
±
3
x
=
−
6
±
3
x
=
−3
，
−9
(12)
2
(
x
＋
2
)
−
16
=
0
x
＋
2
=
±
4
x
=
−
2
±
4
x
=
2
，
−6