Bonsoir,
A=
(3a) (3 - a)
B=
a( a -b)
C=
3b( 2 -b)
D=
3( 5a -7b +2c)
E=
7( 2m+1)
F=
2a(14 + 10a)
G=
m(a -4)
Réponse :
Factoriser, c'est transformer une somme en produit.
A = 9a-3a² = 3²a - 3a² = 3( 3a-a²)
B = a² - ab = aa -ab = a x (a-b)
C = 6b - 3b² = 2x3b - 3b² = 3 x (2b - b²)
D = 15a - 21b + 6c = 3x5a - 3x7b + 2x3c = 3 x (5a - 7b + 2c)
E = 14m + 7 = 7x2m + 7x1 = 7 x (2m + 1)
F = 28a + 20a² = 4x7a + 4x5a² = 4 x (7a + 5a²)
G = ma - 4m = m x (a -4 )