Réponses

2012-09-23T21:01:01+02:00

A=3(x-10)(x+10)+(2x+5) (x+10)

= 3(x² - 10²) + 2x² + 20x + 5x + 50

 = 3x² - 300 + 2x² + 25x + 50

 = 5x² +25x - 250

 

 B=4(3x+6)(5x+1)-2(3x-6)²

 = (12x+24)(5x+1)-(12x-24)²

= 60x² + 12x + 120x + 24 - 12x² + 576x - 576

= 48x² + 708x - 552

 

 C= 4(7x+5)²+4(2x-1)(7x+5)

= (112x + 80)² + (8x - 4)(7x+5)

= 12544x² + 17920x + 6400 + 56x² + 40x - 28x - 20

= 12600x² + 17932x + 6380

 

En espérant t'avoir aidé.