3^(4x - 3) < 27^(x + 1)

3^(4x - 3) < 3^3(x + 1)

3^(4x - 3) < 3^(3x + 3)

4x - 3 < 3x + 3

4x - 3 - 3x < 3x + 3 - 3x

x - 3 < 3

x - 3 + 3 < 3 + 3

x < 6