3^x-1 +5.3^x-1=162
6. 3^x-1=162
3^x-1=27
x-1=3
x=4
\(3^{x-1}\)+5.\(3^{x-1}\)=162
\(\Leftrightarrow\)\(3^{x-1}\)(1+5)=162
\(\Leftrightarrow\)\(3^{x-1}\)=27
\(\Leftrightarrow\)\(3^{x-1}\)=33
\(\Leftrightarrow\)x-1=3
\(\Leftrightarrow\)x=4
Vậy x=4
Ta có : 3x - 1 + 5 . 3x - 1 = 162
\(\Leftrightarrow\)3x - 1 . ( 1 + 5 ) = 162
\(\Leftrightarrow\)3x - 1 . 6 = 162
\(\Leftrightarrow\)3x - 1 = 162 ÷ 6 = 27
\(\Leftrightarrow\)3x - 1 = 33
\(\Leftrightarrow\)x - 1 = 3
\(\Leftrightarrow\)x = 4
Vậy : x = 4
