Réponses

2013-12-16T21:22:38+01:00
Bonsoir
(5x-2)²-(x-7)(5x-2)
1) Développer
25x²-20x+4 - ( 5x²-37x+14)
20x²+17x-10
2) Factoriser
(5x-2)( 5x-2-x+7)
(5x-2)(4x+5)
3) x = 2/5  
(5 * 2/5 - 2 ) (4*2/5+5) = 0 (8/5 + 5 ) = 0