how specific does your answer need to be?
here's how i solve it:
3^x+1 = 5^x log both sides
x+1log3 = xlog5 expand
xlog3 + log3 = xlog5 collect like terms (move x terms together)
log3 = xlog5 - xlog3 pull out common factor ( the x )
log3 = x (log5 - log3) divide!
log3 / (log5 - log3)
= answer (:
hope this helps!