bjr
1 => cf définition cours
2
5(6b+3) = 5*6b + 5*3 = 30b + 15
9y(7y-4) = 9y*7y - 9y*(-4) = 63y² + 36y
-2(8-m) = -2*8 - 2*(-m) = -16 + 2m
12a - 18 = 6*2*a - 9*2 = 2(6a-9)
20c+4c² = 4c*5 + 4c*c = 4c(5+c)
7 + 21k = 7*1 + 7*3k = 7( ... + ... )
3)
a = 3*(-4) - 4(5-4) = -12 - 4 = - 16
b = x(82+33+18+67) = 200x = 200*(-0,08) = -16
c = -6x - 18 - 4x + 18 = -10x = -10*1,6 = -16
