5
x
⋅
9
−
5
x
+
1
=
5
2
x
+
1
⋅
4
5
x
⋅
9
−
5
⋅
5
x
=
5
⋅
5
2
x
⋅
4
5
x
⋅
(
9
−
5
)
=
5
⋅
5
2
x
⋅
4
5
x
⋅
4
=
5
⋅
5
2
x
⋅
4
5
x
=
5
⋅
5
2
x
5
x
−
2
x
=
5
5
−
x
=
5
1
−
x
=
1
x
=
−
1
5^x cdot 9 - 5^{x+1} = 5^{ 2x+1 } cdot 4 newline
5^x cdot 9 - 5 cdot 5^{x} = 5 cdot 5^{ 2x } cdot 4 newline
5^x cdot (9 - 5) = 5 cdot 5^{ 2x } cdot 4 newline
5^x cdot 4 = 5 cdot 5^{ 2x } cdot 4 newline
5^x = 5 cdot 5^{ 2x } newline
5^{x-2x} = 5 newline
5^{-x} = 5^1 newline
-x= 1 newline
x= -1