Réponses

  • Utilisateur Brainly
2014-09-13T16:44:42+02:00
Développer :
(x - 3)(x - 7) - (2x - 7)(x - 3)
= x² - 7x - 3x + 21 - (2x² - 6x - 7x + 21)
= x² - 10x + 21 - 2x² + 6x + 7x - 21
= - x² + 3x

Factoriser :
(x - 3)(x - 7) - (2x - 7)(x - 3)
= (x - 3)(x - 7 - 2x + 7)
= (x - 3) * (- x)
= - x(x - 3)