bonjour,
A = - 2/5
B = 4/7
C = - 3 /2
A + B + C
= - 2/5 + 4/7 - 3/2
= -28/70 + 40/70 - 105/70
= - 93/70
3 A - 1 /2 C
= 3 * - 2/5 - ( - 3/2 : 2 )
= - 6 /5 - ( - 3 /2 * 1/2)
= - 6/5 - ( - 3/4 )
= - 24/20 + 15/20
= - 9 /20
A/B
= - 2/5 : 4 /7
= - 2 /5 * 7/4
= - 14/20
= - 7 /10
AB : C
= ( - 2/5 * 4/7 ) : - 3 /2
= - 8/35 * - 2/3
= - 16/ 105
C + B : A
= - 3/2 + 4/7 : - 2/5
= - 3/2 + 4/7 * - 5/2
= - 3/2 - 20/14
= - 21/14 - 20 /14
= - 41 /14
