factorisation de ( 2 x + 1)² - ( - x + 3)²
= ( 2 x + 4 - x + 3) ( 2 x + 1 + x - 3)
= ( x + 7) ( 3 x - 2)
( différence de 2 carrés)
g(x) = x² - 16 - ( 2 x +8) ( - 2 x + 1)
g(x) = ( x - 4) ( x + 4) - 2 ( x + 4) ( - 2 x + 1)
g(x) = ( x + 4) ( x - 4 + 4 x - 2)
g(x) = ( x + 4) ( 5 x - 6)
3/ 3 x² + 10 x - 8 = - 8
3 x² + 10 x - 8 + 8 = 0
3 x² + 10 x = 0
x ( 3 x + 10) = 0
x = 0 ou - 10/3