А) =(149/12 + 5/3 - 23/6 +11/4):(5/2*2/5 - 7/9)= ( 149+20+46+33):(-7)=
( 12 ) (9)
=248 : (-7) = _ 62 * 9 =_ 62*3 =_ 186 =_ 26 4
12 (9) 3 *7 7 7 7
б) = 12/5 * 15/91 + 8/7 - 112/73 * (40/7 - 81/16) = 36/91 +8/7 - 112/73 * 40/7 + 112/73 *81/16= 36/91 + 8/7 - 640/73 + 567/73 = 36/91 + 8/7 - 1=36 + 104 - 91 =
91
=49/91 = 7/13