при а=5,4 и в=7/36
8/9а-в :35/144
3,2:а-81/84в

1) 8/9 *5,4 - 7/36:35/144 = 8/9* 5 2/5 - 7/36*144/35= 8/9* 27/5 - 1/1*4/5= 8/1*3/5 -4/5 = 24/5 - 4/5= 20/5=42) 3,2 : 5,4 - 81/84*7/36= 3 1/5 : 5 2/5 - 9/12* 1/4= 16/5: 27/5 - 9/48= 16/5*5/27 - 3/16= 16/27- 3/16 = 256/432 - 81/432=  175/432