Réponse :
Explications étape par étape
Bonsoir
Calculer A :
A = 6/5 - 17/14 : 5/7
A = 6/5 - 17/14 x 7/5
A = 6/5 - 7/14 x 17/5
A = 6/5 - 7/(2 x 7) x 17/5
A = 6/5 - 1/2 x 17/5
A = 6/5 - 17/(2 x 5)
A = 6/5 - 17/10
A = (6 x 2)/(5 x 2) - 17/10
A = 12/10 - 17/10
A = (12 - 17)/10
A = (-5)/10
A = -5/(2 x 5)
A = -1/2
Calculer B, écriture décimale puis scientifique :
B = (3 x 10^5 x 4 x (10^(-3))^2) / (16 x 10^(-4))
B = (3 x 4 / 16) x 10^(5-3*2+4)
B = (3 x 4 / (4 x 4)) x 10^(5-6+4)
B = 3/4 x 10^3
B = 0,75 x 1000
B = 750
B = 7,5 x 10^2
