Find the inverse of y = 100 * 2^(x/3)

I don't know how to get y out of the exponent.

y = 100 * 2^(x/3)
x = 100 * 2^(y/3)
x/100 = 2^(y/3)
Take log base 2 of both sides

log[2] (x/100) = log[2] 2^(y/3)
log[2] (x/100) = y/3
3 log[2] (x/100) = y