Réponse :
Bonjour,
1) [-4 x2 -2] x(-10) = (-8-2) x (-10)= -10 x (-10) = 100
2) (49x 10 / 15 x 21 ) + 2/9= 490/315 + (2/9)
= (490 x 9) /(315 x9) + (2 x 315) / (9 x315)
= 4410/2835+ 630/2835
=(4410+630)/2835
=5040/2835
=16/7
Bonne chance!
