bonjour
a = - 1
b = 1/3
c = 2/5
A = a/b + c
A = ( - 1 : 1/3) + 2 /5
A = ( - 1 * 3) + 2/5
A = - 3 + 2/5
= - 15/5 + 2/5
= - 13 /5
B = ( a + b ) / c
= ( - 1 + 1 /3 ) / 2/5
= ( - 3/3 + 1/3) / 2/5
= - 2 /3 * 5/2
= - 10/6 = - 5 /3
C = a / ( b + c )
= - 1 : ( 1/3 + 2/5)
= - 1 : ( 5/15 + 6/15)
= - 1 : 11/15
= - 1 * 15/11
= - 15/11
si a = 1/2 et B = - 5/4 et c = 3/4
B = ( 1/2 - 5/4) / 3 /4
= - 3/4 x 4/3 = - 12 /12 = - 1
C = 1/2 : ( - 5/4 + 3 /4)
= 1 /2 ; - 2/4
= 1/2 * - 4/2
= - 4 /4 = - 1
donc elle a raison
