Réponses

  • Omnes
  • Modérateur confirmé
2014-02-16T16:56:27+01:00
Salut,

A = 4x-5
B = 1+3x

A² = (4x-5)² = (4x)² - 2*4x*5 + 5² = 16x² - 40x + 25
B² = (1+3x)² = 1² + 2*3x*1 + (3x)² = 1 + 6x + 9x²
(A+B)(A-B) = [(4x-5)+(1+3x)][(4x-5)-(1+3x)] = (4x-5+1+3x)(4x-5-1-3x) = (7x -4)(x-6)
=7x² - 42x -4x + 24 = 7x² -46x + 24

Bonne journée !