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2013-11-20T21:27:11+01:00
Bonsoir

A= 3(x-10)(x+10)+(2x+5)(x+10)
A =( 3x -30)(x+10) + 2x² +20x +5x +50
A = 3x² +30x +30x - 300 +2x² +25x +50
A = 5x² +85x -250

B= 4(3x+6)(5x+1)-2(3x-6)
B = (4x+24)(5x+1) - 2(9x² - 36 x +36)
b = 20x² +4x +120x +24 - 18x² + 72x - 72
B = 2x² +196 x -48

C= 4(7x+5)+4(2x-1)(7x+5)

C = 4 (49x² + 70x +25) + (8x -4)(7x+5)
C = 196x² + 280x + 100 + 56x² +40x -28x -20
c = 252x² +292x +80