Problème de factorisation qui peut m'aider à ces deux exrercices merci merci merci

Bonjour,

A = 16x + 4
A = 4(4x + 1)

B = 9 - 72x
B = 9(1 - 8x)

C = 12 - 8x
C = 4(3 - 2x)

D = -6x - 18
D = -6(x + 3)

E = 9x + 6
E = 3(3x + 2)

F = 42 - 14x
F = 14(3 - x)

Exercice 7 :

A = 54 - 18a
A = 18(3 - a)

B = -49 + 21x
B = 7(-7 + 3x)

C = -36z + 63
C = 9(-4z + 7)

D = 5b + 25
D = 5(b + 5)

E = 3x^2 + x
E = x(3x + 1)

F = 8t^2 + 2t
F = 2t(4t + 1)

G = -x + 3x^2
G = x(-1 + 3x)

H = 3y^2 + 9y^2
H = 3y^2(1 + 3)
H = 12y^2