a) \(3^{x + 1} = 81\)
\(3^{x + 1} = 3^{4}\)
x + 1 = 4
x = 3
Vậy ..............
b) \(3^{x}.9^{2}= 729\)
\(3^{x}= 729 : 81 = 9\)
\(3^{x}= 3^{2}\)
=> x = 2
Vậy ................
c) \((x^{2})^{3}= 4096\)
\(x^{6}= 4096\)
\(x^{6}= 4^{6}\)
=> x = 4
Vậy ................