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Exercice 72 

a. 
A =  - 2 + x( -5x + 7 ) 
A = - 2 - 5x² + 7x
A = - 5x² + 7x - 2

B = ( x - 1 ) ( - 5x + 2 )
B = - 5x² + 5x + 2x - 2
B = - 5x² + 7x - 2 

C = x ( - 5x + 5 ) + 2 ( x - 1 ) 
C = - 5x² + 5x + 2x - 2
C = - 5x² + 7x - 2

D = - 5x ( x - 2 ) - ( 3x + 2 ) 
D = - 5x² + 10x - 3x - 2 
D = - 5x² + 7x - 2 

On voit que A=B=C=D

bonjour

a = - 2 - 5 x² + 7 x = - 5 x² + 7 x - 2

b = - 5 x² + 2 x + 5 x - 2 = - 5x² + 7 x - 2

c = - 5 x²  + 5 x + 2 x - 2 = - 5 x² + 7 x - 2