`text{Bài 2}`
`c ) 2 . 3^{2 . x - 1} - 13 = 41`
`2 . 3^{2 . x - 1} = 41 + 13`
`2 . 3^{2 . x - 1} = 54`
`3^{2 . x - 1} = 54 : 2`
`3^{2 . x - 1} = 27`
`3^{2 . x - 1} = 3^3`
`=> 2 . x - 1 = 3`
`2 . x = 3 + 1`
`2 . x = 4`
`x = 4 : 2`
`x = 2`
`text{Vậy x = 2}`
`#dtkc`