Bonjour
5 x² - 4 x + 1
si x = 4
5 * 4² - 4 *4 + 1 = 80 - 16 + 1 = 65
( 3 x - 1 )² - 4 ( x² + 1 ) = 5 x² - 6 x - 3
9 x² - 6 x + 1 - 4 x² - 4 = 5 x² - 6 x - 3
5 x² - 6 x - 3 = 5 x² - 6 x - 3
( 3 x - 1 )² - 4 ( x² + 1 ) = 5 x² - 4 x + 1
9 x² - 6 x + 1 - 4 x² - 4 = 5 x² - 4 x + 1
9 x² - 4 x² - 5 x² - 6 x + 4 x = 1 - 1 + 4
- 2 x = 4
x = - 4/2 = - 2