Sin(Пx/6)=-1
Пx/6=-П/2+2Пn
x=-3+12n
8*2/3:(5/6x-5/3)-19/40=21/40
8*2/3:5x-10/6-19/40=21/40
8*2/3:5x-10/6-19/40=21/40
8*2/3*6/5x-10-19/40=21/40
8*2*2/5x-10-19/40=21/40
32/5x-10=19/40=21/40
32/5x-10=21/40+19/40
32/5x-10=21+19/40
21/5x-10=40/40
32/5x-10=1
32=5x-10
-5x=-10-32
-5x=-42
x=42/5
x=8 2/5
Ответ: 8 2/5
НОК(480,180,450)=2*2*2*2*2*3*3*5*5=7200
480=2*2*2*2*2*3*5
180=2*2*3*3*5
450=2*3*3*5*5
7200:480=15⇒ 105\7200
7200:180=40⇒ 920\7200
7200:450=16⇒ 496\7200