Bonjour, comment on calcul : (en développant puis réduire) A = (2x + 5) (5x - 1) - (2-5x) (3x + 2) B = (3x - 4)² + (6x + 7) (6x - 7) Merci d'avance!

Bonjour,

A = (2x + 5) (5x - 1) - (2-5x) (3x + 2)
A = 10x² - 2x + 25x - 5 - (6x + 4 - 15x² - 10x)
A = 10x² - 2x + 25 - 5 - 6x - 4 + 15x² + 10x
A = 10x² + 15x² -2x - 6x + 10x + 25 - 5 - 4
A = 25x² + 2x + 16

B = (3x - 4)² + (6x + 7) (6x - 7)
B = 9x² - 24x + 16 + 36x² - 42x + 42x - 49
B = 9x² + 36x² - 24x + 16 - 49
B = 45x² - 24x - 33

bonjour

A = (2x + 5) (5x - 1) - (2-5x) (3x + 2)
a = 10x²-2x+25x-5 -(6x+4-15x²-10x)
a = 10x²+23x-5 +15x² +4x-4
a = 25x²+27x-9

B = (3x - 4)² + (6x + 7) (6x - 7)
b = 9x²-24x+16 +36x²-49
b = 45x²-24x -33