Bonsoir,
calculer en détaillant les étapes de calculs en simplifiant
A= 2/7+-8/5= (2x5-8x7)/(7x5)= (10-56)/35= -46/35
B= 13/2-9/5= (13x5-9x2)/(2x5)= (65-18)/10= 47/10
C=3/7x8/9= (3x8)/(7x9)= 24/63= 8/21 on a divisé par 3
D=21/4x-5/7= -(21x5)/(4x7)= -105/28= -15/4 on a divisé par 7
E=13/2:4/5= (13/2)x(5/4)= (13x5)/(2x4)= 65/8.
F=10/11:13/5= (10/11)x(5/13)= (10x5)/(11x13)= 50/143
G=2/30+4/5x7/3= 2/30+(4x7)/(5x3)= 2/30+28/15= (2+28x2)/30= 58/30= 29/15
H=8/7:(9/25+13/5)= (8/7)/ (9/25+13x5)/25= (8/7)/(9+65)/25= (8/7)/(74/25)
= (8/7)x(25/74)= (8x25)/(7x74)= 200/518= 100/259
