x4-1=27
=>x4-1=33
=>x3=33(vì 4-1=3)
=> x=3
3x-1=27
=>3x-1=33
=>x-1=3
=>x=2
a) Ta có: x4-1 = 27
Mà 33 = 27
x3 = 33
Vậy x = 3
b) Ta có: 3x-1 = 27
Mà 33 = 27
=> 3x-1 = 33
=> x - 1 = 3
=> x = 3+1=4
Vậy x = 4
x4 - 1 = 27
x3 = 27
x3 = 33
=> x = 3
3x - 1 = 27
3x - 1 = 33
x - 1 = 3
x = 3 + 1
x = 4
x 4 - 1 = 27
x 3 = 27
x 3 = 3 3
=> x = 3
3 x - 1 = 27
3 x - 1 = 3 3
=> x - 1 = 3
x = 4
a, \(x^{4-1}=27\)
\(\Leftrightarrow x^3=3^3\)
\(\Leftrightarrow x=3\)
b, \(3^{x-1}=27\)
\(\Leftrightarrow3^{x-1}=3^3\)
\(\Leftrightarrow x-1=3\)
\(\Leftrightarrow x=3+1=4\)
x^4-1=27
x^3=3^3
=>x=3
3^x-1=27
3^x-1=3^3
=>x-1=3
=>x=4