That would be 1925 ( 15 + 05 = 19 and 10 + 15 = 25)
Remember these two combinations: logab=loga+logb, log(a/b)=loga-logb
3logx=logx^3
(1/2)log(x+2)=log(x+2)^(1/2)
2log(z-4)=log(z-4)^2
so the given expression can be combined into log{[(x^3)(z-4)^2]/(x+2)^(1/2)}