bonsoir
A= 2 (ax² + bx + c) = 2 a x² + 2 b x + 2 c
B= 4x (ax + b - c) = 4 a x² + 4 x b - 4 x c
C= (2xy - 3y)² = 4 x²y² - 12 x y² + 9 y²
D= ( 2ac -3x) (2ac +3x) = 4 a²c² + 6 a c x - 6 a c y - 9 x² = 4 a² c² - 9 x²
E= (2a - c) ( 3 cx +1) = 6 a c x + 2 a - 3 x c² - c
Factoriser:
F= 2ax² + 2ax = 2 a x ( x + 1)
G= 2x² - ax + 3bx = x ( 2 x - a + 3 b )
H= 4a² x² + 8ax + 1 = ( 2 a x + 1)²
I = 64c² -1 = ( 8 x -1) ( 8 c + 1)
J= (ax + bx)² - (ax - bx)² = ( a x + b x + a x - b x) ( a x + b x - a x + b x)
= (2 a x) ( 2 b x)