Question 546249
First you must put everything out in front of the logarithms in the exponents
log5 x^3 + log5 (x+1) - log5 4

Now you must combine the adding by multiplying them
log5 (x^3(x+1)) - log5 4

However you can still simplify
log5 (x^4+x^3) - log5 4

Next you add the subtracted part by dividing and dividing is just like multiply by the reciprocal so you get...
log5 ((x^4+x^3)/(4))