Réponse :
Explications étape par étape
A = 12 / (-5/7) (a/b) / (c/d) = a/b * d/c
= 12 * (-7/5)
= -84/5
B = (3/5) / (5/6) (a/b) / (c/d) = a/b * d/c
= 3/5 * 6/5
= 18/25
C = 4/(2/3) - (1/4)/2
= 4 * 3/2 - (1/4 * 1/2)
= 6 - 1/8
= (48 - 1 ) / 8
= 47/8
D = ( 5/7 - 1) / ( 4/9 + 5/3 )
= ( -2 / 7 ) / ( 19/9 )
= -2/7 * 9/19
= -18/133
E = [ -9/14 + 2/7 ] / [ 2/3 + 1/2 ]
= [ ( -9 + 4 ) / 14 ] / [ (4 + 3 ) / 6 ]
=(-5 / 14 ) / ( 7/ 6 )
= -5 / 14 * 6 / 7
= -5 / 7 * 3 / 7
= - 15/49
