Les exercices 29 et 30 svp!

Bonjour

a) 17 x 72 + 17x 28 = 17 x 100 = 1700
b) 11.5 x 4.6 - 1.5 x 4.6 = 4.6 x 10 = 46
c) 121 x 4.01 - 4.01 x 21 = 4.01 x 100 = 401
d) 1,005 x 8.5 + 3.,995 x 8.5 = 8.5 x 5 = 42.5

a) 12x +12 y = 12 (x +y)
b) 7x -4x = x (7-4) = x(3)
7a + 7b = 7 (a +b)
12m -5 m  = m( 12 -5) = m(7)