bonjour
exo 1 :
a = 49x² - 16
a = 7 * 7 * x * x - 8 * 2
a = 7x (8 - 2)
b = 64 - 80x + 25²
b = 8 * 8 - 8 * 10 * x + 5 * 5
b = 8 (5 - x + 10)
exo 2 :
c = 49 - (3x + 2)²
c = 49 - (3x + 2) (3x + 2)
c = 49 - 3x * 3x + 3x * 2 + 2 * 3x + 2 * 2
c = 49 - 9x² + 6x + 6x + 4
c = 49 - 9x² + 12x + 4
c = 45 + 9x² + 12x
d = 49 - (3x + 2) (3x + 2)
d = (3x + 2) - 49