Найдите значение выражений 7/36+1/5+5/36; б) 19/42-(5/42+1/5); в) (1/6+7/15)-2/15.   / это дробь

= 7×5/36×5 + 1×36/5×36 + 5×5/36×5 = 35 + 36 + 25 /180 = 96/180 = 8/15 = 19/42 - (5/42 + 1/5) = 19×5/42×5 - (5×5/42×5 + 1×42/5×42) = 95/210 - (25 + 42/210)= 95/210 – 67/210= 28/210 = 2/15 = (1×5/6×5 + 7×2/15×2) – 2×2/15×2= 5+14/30 – 4/30 = 19-4/30= 15/30 = 1/2

а)8\15 б)8\15 в)15\30или 1\2