Réponse :
Bonsoir
Explications étape par étape :
A=3/4+5/7
A = (3*7)/(4*7) + (5*4)/(7*4)
A = (21/28) + (20/28)
A = 41/28
B=7- 5/9
B = (7*9)/9. - 5/9
B = (63/9) - 5/9
B = 58/9
C=2/3×3/4-1/4
C = (2*3/3*4) - 1/4
C = (6/12) - 1/4
C = (6/12) - (1*3/4*3)
C = (6/12) - (3/12)
C = 3/12
C = (1*3)/(4*3)
C = 1/4
D= 11/9÷5/3
D = 11/9 * 3/5
D = (11*3)/(3*3*5)
D = 11/15