18:3=6 27:3=9 42:3=14 60:3=20
5x+13=3x+57
5x-3x=57-13
2x=44
x=22
3 ( 5/16 ) + 1/4 - 2 ( 1/16 ) = 1 ( 4/16 ) + 4/16 = 1 ( 8/16 ) = 1 ( 1/2 )
-----------------------------------
6 ( 11/12 ) - 3 ( 1/6 ) - 1 ( 1/4 ) = 6 ( 11/12 ) - 3 ( 2/12 ) - 1 ( 3/12 ) =
= 6 ( 11/12 ) - 4 ( 5/12 ) = 2 ( 6/12 ) = 2 ( 1/2 )
----------------------------------
3 ( 7/9 ) - 1 ( 5/18 ) + 3 ( 1/2 ) = 3 ( 14/18 ) + 3 ( 9/18 ) - 1 ( 5/18 ) =
= 6 ( 23/18 ) - 1 ( 5/18 ) = 5 ( 18/18 ) = 6
12у-9у+15=27
3у=27-15
3у=12
у=12:3
у=4
Ответ:4