Bonjour,

P = ( 2 - 4/7 )/5

2/1 - 4/7 = 14/7 - 4/7 = 10/7

10/7 ÷ 5/1 = 10/7 × 1/5 = 10/35 = ( 10 ÷ 5 ) / ( 35 ÷ 5 ) = 2/7

Q = 1 - 2/( 3 + 1/3 )

1 - 2/(9/3 + 1/3)

1 - 2 ÷ 10/3 = 1 - 2 × 3/10 = 1 - 6/10

10/10 - 6/10 = 4/10 = ( 4 ÷ 2 ) / ( 10 ÷ 2 ) = 2/5

S = 4/5 - 7/5 × ( 2 + 5/6 )

S = 4/5 - 7/5 × 17/6

S = 4/5 - 119/30 = 24/30 - 119/30

S = (-95)/30 = ( -95 ÷ 5 ) / ( 30 ÷ 5 ) = (-19)/6

T = ( 3 + 6/7 ) / ( 3 - 6/7 ) = ( 21/7 + 6/7 ) / ( 21/7 - 6/7 )

T = 27/7 ÷ 15/7 = 27/7 × 7/15

T = 189/105 = ( 189 ÷ 21 ) / ( 105 ÷ 21 ) = 9/5

Bonne journée :)