To solve for x, we can use the properties of logarithms:

log3x = log3(a^3) - log3(b^2) + log3(a+b)
log3x = log3(a^3 / b^2) + log3(a+b)
x = a^3 / b^2 * (a+b)
x = a^4 / b^2 + ab