Bonjour,

Exercice 3 :

A = ( -8/7 - 5 ) / ( -9/2 + 5 )

A = ( -8/7 - 35/7 ) / ( -9/2 + 10/2 )

A = -43/7 ÷ 1/2 = -43/7 × 2/1

A = -86/7

B = 5/3 × ( 11/8 + 3/13 )

B = 5/3 × ( 143/104 + 24/104 )

B = 5/3 × 167/104

B = 835/312

C = 3/5 - 12/25 × -20/3

C = 3/5 - ( 12/25 × -20/3 )

C = 3/5 - ( -240/75 )

C = 3/5 - ( -16/5 )

C = 3/5 + 16/5

C = 19/5