Réponses

2014-10-09T17:31:17+02:00
A = (5x+6)²+(4-9x)(4+9x)
a = 25x² + 60x + 36 + 16 + 28x - 28x - 81x²
a = -56x² + 60x + 52

b = 
(3x-7)(5-8x)-(2x-5)²
b = 15x - 24x² - 35 + 56x - (4x² - 20x + 25)
b = 15x - 24x² - 35 + 56x - 4x² + 20x - 25
b = -28x² + 91x - 60

c = 38²
c = (40 - 2)²
c = 40² - 160 + 2²
c = 1600 - 160 + 4
c = 1440 + 4
c = 1444