Упростите выражение: 1) 5/8 a * 4/15 b; 3) 13/24 d * 32c; 2) 6 3/4 x * 1 11/45 y; 4) 18 1/3 a * 1 2/11 b * 9/13 c.

1) 5/8 a * 4/15 b=1/2 a * 1/3 b=1/6 ab; n
2) 6 3/4 x * 1 11/45 y=27/4 x * 56/45 y=3/1 x * 14/5 y=42/5 ху=8 2/5 ху;n
3) 13/24 d * 32c=13/24 d * 32/1 c=13/3 d * 4/1 c=52/3 dc=17 1/3 dc;n
4) 18 1/3 a * 1 2/11 b * 9/13 c=55/3 a * 13/11 b * 9/13 c=5/1 a * 1/1 b * 3/1 c=15аbс.