1. correction
log((100A^2)/(B^4*C^(1/3)))
(log((10^2)+log(A^2))-(log(B^4)+log(C^(1/3)))
(2log((10)+2log(A))-(4log(B)+(1/3)log(C))
2log((10)+2log(A)-4log(B)-(1/3)log(C)
2*1+2*a-4*b-(1/3)*c
2+2a-4b-(1/3)c
2 a - 4 b - c/3 + 2
2. correct
just simplify 5log(4)=5log(2^2)=5*2log(2) =10log(2)
