Réponses

2013-03-24T13:46:12+01:00

Bonjour,

 

Quelle est la consigne du 42 et du 43 ? Je suppose "factoriser" ?

 

Exercice 42 :

 

A = (7x-1)²+(7x-1)²

A = (7x-1)(7x-1)+(7x-1)(7x-1)

A = (7x-1)[(7x-1)+(7x-1)]

A = (7x-1)(7x-1+7x-1)

A = (7x-1)(14x-2)

 

B = (5a-4)(a+2)-(a+2)²

B = (5a-4)(a+2)-(a+2)(a+2)

B = (a+2)[(5a-4)-(a+2)]

B = (a+2)(5a-4-a-2)

B = (a+2)(4a-6)

 

Exercice 44 :

 

a) (x+3)² = +6x+9

b) (2x-5)² = 4x²-20x+25

c) (7x+8)(7x-8) = 49x²-64

 

:)