Verified answer

Ответ:

Пошаговое объяснение:

1/2*(-1)*2log2(3)+log2(15)-log2(20)= -log2(3)+log2(15)-log2(20)= log2(15/3)-log2(20)= log2(5)-log2(20)= log2(5/20)= log2(1/4)= -2