5) (3/14+5/7)÷3 5/7
5/7=10/14
3 5/7=26/7
3/14+10/14=13/14
13/14÷26/7=13/14 × 7/26=(13×7)÷(14×26)=(13×7)÷(7×2×13×2)=1/4
6) 19/24÷(3/16+5/24)=19/24÷(9/48 + 10/48)=19/24÷19/48=19/24×48/19=2
5) 3/7 x=1 4/5
Х=1 4/5 ÷3/7
1 4/5=9/5=63/35
3/7=15/35
1 4/5 ÷ 3/7=63/35 ÷ 15/35=63/35 × 35/15=63/15=4 3/15=4 1/3
6) не вижу до конца