Bonjour pouvez-vous m'aider à mon exercice, je ne comprend pas merci d'avance.

bonjour

f(x) = 4x² - 12x + 9 - (3x+12) (-2x+3)

= 4x² - 12x + 9 - (-6x² + 9x - 24 x + 36)

= 4x² + 6x² - 12 x - 9x + 24 x + 9 - 36

= 10x² + 3x - 27

f(x) = 4x² - 12x + 9 - (3x+12) (-2x+3)

= (2x-3)² - (3x+12) (-2x+3)

= (2x-3)² + (3x+12) (2x-3)

= (2x-3) [(2x-3) + (3x+12)]

= (2x-3) (5x+9)

f(x) = 0

soit (2*0-3) (5*0+9) = (-3) * 9 = -27

f(x) = -27

10x² + 3x - 27 = - 27

10x² + 3x = 0

x (10x+3) = 0

soit x = 0

soit 10x+3 = 0 => x = -3/10

(2x-3) (5x+9) = 5x+9

2x-3= 0

x = 3/2

10x² + 3x - 27 = 3x + 30

10x² = 57

x² = 57/10

x= -√57/10

ou x = √57/10