exo 29
-2/7 x14/16 = -2/7 x 7/8 = -14 /56 = -7/28
-3/5 x -15/7 = 45 / 35 = 9 / 7
-4/3 x 3/5 = -12 /15 = -4/5
exo 32
3/10 x 5/12 = 15 /120 = 5/40 = 1/8
25/16 x 12/15 = 25/16 x 4/5 = 100 / 80 = 10/ 8 = 5/4
-9 /28 x 56 /63 = - 504 /1764 = - 252/ 882 = - 126/ 441 = - 42/ 147 = -14 /49 =
-2 /7
exo 33
5/7 x4/3 x-1 / 2 = -20 / 42 = -10 /21
-3/ 5 x -1/2 x -2 /7 = -6 / 70 = -3/35