3^(x+1) = 27 (assuming you mean that the 1 is part of the exponent)
(x+1)Log[3] = Log[27] (take the log of both sides)
x+1 = Log[27]/Log[3] (divide by Log[3])
x+1 = 3 (compute Log[27]/Log[3])
x = 2
(x+1)Log[3] = Log[27] (take the log of both sides)
x+1 = Log[27]/Log[3] (divide by Log[3])
x+1 = 3 (compute Log[27]/Log[3])
x = 2