Bonjour;
A= 5a + 5x5
5(a+5)
B= 16b+ 24
8(2b+3)
C = (x+1)(x-3)+7(x + 1)
(x+1)( x-3+7)
= (x+1)( x+4)
D=(3x-1)² + (3x-1)
(3x-1) (3x-1 +1)
= (3x-1) ( 3x)
E= x²-49
(x-7)(x+7)
F= (x+5)²-36
=(x+5-6) (x+5+6)
= (x-1) ( x+11)
G = (2x-4)( 7-x)-(2x-4)²
(2x-4) ( 7-x -2x+4)
= (2x-4) ( -3x +11)
H = 81x2 (3x+1)²
I= x² + 4x+4
(x+2)²
J = 4x²-28x +49
= (2x-7)²