1) log5(0,2) + log0,5(4) = log5(1/5) + log1/2(4) = -1 - 2 = -3
2) log5(9)*log3(25) = log5(3²) * log3(5²) = 2log5(3)*2log3(5) = 2*2 = 4
3)(log7(13))/(log49(13)) = (log7(13))/(2log7(13)) = 2
4)(9^log5(50))/(9^log5(2)) = 9^log5(50/2) = 9^2 = 81
5) (1-log2(12))*(1-log6(12)) = (log2(2)-log2(12))*(log6(6)-log6(12)) = log2(1/6)*log6(1/2) = (-1)log2(6)*(-1)log6(2) = 1.