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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
−
4
)
=
81
(2)
2
(
x
＋
9
)
=
100
(3)
2
(
x
−
7
)
=
49
(4)
2
(
x
＋
2
)
=
9
(5)
2
(
x
＋
10
)
−
49
=
0
(6)
2
(
x
＋
2
)
−
7
=
0
(7)
2
(
x
＋
7
)
=
36
(8)
2
(
x
−
7
)
−
9
=
0
(9)
2
(
x
−
4
)
=
2
(10)
2
(
x
＋
7
)
−
81
=
0
(11)
2
(
x
−
1
)
=
9
(12)
2
(
x
−
5
)
−
25
=
0
©2025 数学クラブ http://sugaku.club/
月 日（ ）
【解答例】
(1)
2
(
x
−
4
)
=
81
x
−
4
=
±
9
x
=
4
±
9
x
=
13
，
−5
(2)
2
(
x
＋
9
)
=
100
x
＋
9
=
±
10
x
=
−
9
±
10
x
=
1
，
−19
(3)
2
(
x
−
7
)
=
49
x
−
7
=
±
7
x
=
7
±
7
x
=
14
，
0
(4)
2
(
x
＋
2
)
=
9
x
＋
2
=
±
3
x
=
−
2
±
3
x
=
1
，
−5
(5)
2
(
x
＋
10
)
−
49
=
0
x
＋
10
=
±
7
x
=
−
10
±
7
x
=
−3
，
−17
(6)
2
(
x
＋
2
)
−
7
=
0
x
＋
2
7
=
±
x
7
=
−
2
±
(7)
2
(
x
＋
7
)
=
36
x
＋
7
=
±
6
x
=
−
7
±
6
x
=
−1
，
−13
(8)
2
(
x
−
7
)
−
9
=
0
x
−
7
=
±
3
x
=
7
±
3
x
=
10
，
4
(9)
2
(
x
−
4
)
=
2
x
−
4
2
=
±
x
2
=
4
±
(10)
2
(
x
＋
7
)
−
81
=
0
x
＋
7
=
±
9
x
=
−
7
±
9
x
=
2
，
−16
(11)
2
(
x
−
1
)
=
9
x
−
1
=
±
3
x
=
1
±
3
x
=
4
，
−2
(12)
2
(
x
−
5
)
−
25
=
0
x
−
5
=
±
5
x
=
5
±
5
x
=
10
，
0