Bonjour
Développer puis factoriser A(x).
A(x)=16x ² - 25 - 3(4x+5)(x-2)
1. Développer A(x).
A(x)=16x ² - 25 - 3(4x+5)(x-2)
A (x) = 16x² - 25 - (12x - 15) (x - 2)
A (x) = 16x² - 25 - (12x² - 24x - 15x + 30)
A (x) = 16x² - 25 - 12x² + 24x - 15x + 30
A (x) = 16x² - 12x² + 24x - 15x - 25 + 30
A (x) = 4x² + 9x + 5
2.Factoriser A(x).
A(x)=16x ² - 25 - 3(4x+5)(x-2)
A (x) = (4x)² - 5² - 3 (4x + 5) (x - 2)
A (x) = (x + 1) (4x + 5)
