Factoriser (2x + 3 )(x - 5) + (x - 5)(4x + 2) (x - 1)(2x + 7) - (2x + 7)(3x - 4) Factoriser avec les identités remarquables x² - 81 36 x² - 49 (Aider moi svp )

bonjour


( 2 x + 3) ( x - 5) + ( x - 5) ( 4 x + 2) 
= ( x - 5) ( 2 x + 3 + 4 x + 2)
= (x - 5)  ( 6 x + 5) 

(x -1) ( 2 x + 7) - ( 2 x + 7) ( 3 x - 4)
= ( 2 x + 7) ( x - 1 - 3 x + 4)
 = ( 2 x + 7) ( - 2 x + 3) 

x² - 81 = ( x - 9) ( x + 9) 

36 x² - 49 = ( 6 x - 7) ( 6 x + 7) 

Bonjour,

A = (2x+3)(x-5) + (x-5)(4x+2)
A = (x-5)((2x+3)+(4x+2))
A = (x-5)(2x+3+4x+2)
A = (x-5)(6x+5)

B = (x-1)(2x+7) - (2x+7)(3x-4)
B = (2x+7)((x-1)-(3x-4))
B = (2x+7)(x-1-3x+4)
B = (2x+7)(-2x+3)

C = x² - 81
C = x² - 9²
C = (x-9)(x+9)

D = 36x² - 49
D = (6x)² - 7²
D = (6x-7)(6x+7)