Réponse :
Explications étape par étape
forme a²-b² = (a+b) (a-b)
A = 25x²-49 = (5x+7) (5x-7)
B = (4x-3)² -64 = (4x-3+8) (4x-3-8) = (4x+5) (4x-11)
C = (9 -36x²) = (3-6x) (3+6x) = (-6x+3) (6x+3)
D = (x-1)² -(5x+3)² = (x-1 +5x+3) (x-1 -5x-3) = (6x+2) (-4x-4)
E = 16x²-(3x+5)² = (4x+3x+5) (4x-3x-5) = (7x+5)(x-5)
F = (2x+7) ( (5x-3) + (3x+8) ) = (2x+7) (8x+5)
G = (x-6) .( ( 2x+5) -2) = (x-6) (2x+3)
H = 9x²-27x+9 = 9(x²-3x+1)
complétion de carré
=9(x²-3x+9/4 -9/4 +1)
= 9( ( x - 3/2 )² -5/4 )
= 9( ( x-3/2)+√5/4) ( (x-3/2) -√5/4) )
I = (x-1) ( (5x-3)- (6x-5) ) = (x-1 ) ( -x+2)
J = (2x-3)² -100 = ( (2x-3) +10) ((2x-3) -10) = (2x+7) ( 2x-13)
K = (3x+5) ( ( 8x-6) -2) = (3x+5) ( 8x-8)
L = (4x-3)² - (2x-9)² = (4x-3+2x-9) (4x-3-2x+9) = (6x-12) (2x+6)
M = 14x² -21xy +7x = 7x(2x-3y+1)
