maths Factorisation merci

A = 4b² - 8b + 20
= (2b)² - 2*2b*2 + 2² -2² +20
= (2b-2)² + 16
= (2(b-1))² + 4²
= 4(b-1)² + 4²
= 4 ((b-1)²+4)
B = (x-3)(2x+1) - (x+5)(x-3)
= (x-3) ( (2x+1) - (x+5) )
= (x-3) (x-4)
C = 2x-8 + (x-4)(5x+1)
= 2(x-4) + (x-4)(5x+1)
= (x-4) ( 2+ (5x+1) )
= (x-4) ( 5x+3 )
D = (7x+1)² + (x-3)(7x+1)
= (7x+1) ( (7x+1) + (x-3) )
= (7x+1) ( 8x-2 )
E= (5x+2) (4x+7) + 5x+2
= (5x+2) (4x+7+1)
= (5x+2) (4x+8)
F= 36x²+60x+25
= (6x)² + 2*6x*5+5²
= (6x+5)²
G= 49x²-42/5x + 9/25
= (7x)² - 2*7x*3/5 + (3/5)²
= (7x - 3/5 ) ²

En espérant t'avoir aidé! =)