Réponse :

Explications étape par étape

Bonjour

A = 1/2 + 7/5

A = 5/10 + 14/10

A = 19/10

B = 8/7 - 7/12

B = 96/84 - 49/84

B = 47/84

C = 2/23 - 11/10

C = 20/230 - 253/230

C = -233/230

D = -3/4 - 7/9

D = -27/36 - 28/36

D = -55/36

28)

A = 2/7 + 1/9

A = 18/63 + 7/63

A = 25/63

B = 8/3 - 3/5

B = 40/15 - 9/15

B = 31/15

C = 15/2 + -7/3

C = 45/6 - 14/6

C = 31/6

Verified answer

Bonsoir,

25)

a. 1/2 + 7/5 = (1 x 5) / (2 x 5) + (7 x 2) / (5 x 2) = 5/10 + 14/10 = 19/10

b. 8/7 - 7/12 = (8 x 12) / (7 x 12) - (7 x 7) / (12 x 7) = 96/84 - 49/84 = 47/84

c. 2/23 - 11/10 = (2 x 10) / (23 x 10) - (11 x 23) / (10 x 23) = 20/230 - 253/230 = - 233/230.

d. - 3/4 - 7/9 = (- 3 x 9) / (4 x 9) - (7 x 4) / (9 x 4) = - 27/36 - 28/36 = - 55/36

28)

a. 2/7 + 1/9 = (2 x 9) / (7 x 9) + (1 x 7) / (9 x 7) = 18/63 + 7/63 = 25/63.

b. 8/3 - 3/5 = (8 x 5) / (3 x 5) - (3 x 3) / (5 x 3) = 40/15 - 9/15 = 31/15.

c. 15/2 + - 7/3 = (15 x 3) / (2 x 3) - (7 x 2) / (3 x 2) = 45/6 - 14/6 = 31/6.