Sagot :
Bonjour,
1. A = (−8)/21 + 3/7
= (-8/21 + 3/7 * 3/3
= (-8/21) + 9/21
= 1/21
2. B = 2/7 - 3/11
= (2/7* 11/11) - (3/11* 7/7)
= 22/77 - 21/77
= 1/77
3. C = 8/5 x 40
= (8*5) / 40
= 40/40
= 1
4. D = (81/12)/ (-27)/16
= 81/12 * -16/27
= - 1 296/ 324
on divise par 9
= - 144/36
on divise par 4
= -36/9
on divise par 9
= - 4