а) -7 3/14+2,6=-101/14 +26/10=1010/140+364/140=1374/140
1374/140+(-2⅗)=1374/140-13/5=1374/140-364/140=1010/140=505/70=101/14=7 целых 3/14
б)(-14,7-2,9)-(3,5-1⅕)=-17,6-(3,5-1,2)=-17,6-2,3=15,3
в) незнаю
