Réponses

2013-05-19T17:49:40+02:00

x(x-1)+3(x+4)=(x-3)(x+5)

 

x² -x +3x +12 = x² +5x -3x -15

x² +2x +12 = x² +2x -15

x²-x² +2x -2x = -15 -12

0 + 0 = - 27