Bonsoir
5 x (3+4) = 5 (3+4)
9 x a + 6 x b = 9a + 6b
(7,2 - 6,9) x 2,5
a + b + a x b =a + b + ab
(a+b) x (a-b) = (a+b) (a-b)
a x (b+c) x (x+y) = a (b+c) (x+y)
