Sagot :
A = 7/5 - (2/5 * 15/4) = 7/5 - [ ( 2*15) / (5*4) ] = 7/5 - 30/20
A = [ ( 7*4) / (5*4) ] - 30/20 = 28/20 - 30/20 = -2/20 = -1/10
B = ( 5/6 - 3/8) / (2+5/3) = [ ( 5*8) / (6*8) - (3*6)/(8*6)] / [ (6/3 + 5/3)]
B = ( 40/48 - 18/48) / (6/3 +5/3) = (22/48) / 11/3) = 66/528 = 1/8
A = [ ( 7*4) / (5*4) ] - 30/20 = 28/20 - 30/20 = -2/20 = -1/10
B = ( 5/6 - 3/8) / (2+5/3) = [ ( 5*8) / (6*8) - (3*6)/(8*6)] / [ (6/3 + 5/3)]
B = ( 40/48 - 18/48) / (6/3 +5/3) = (22/48) / 11/3) = 66/528 = 1/8