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 = x²+6x+9
b) (2x-5)² = 4x²-20x+25
c) (7x+8)(7x-8) = 49x²-64
:)
