Réponses

2013-03-11T18:56:03+01:00

1) 20x²-60x+45-(2x²+14x-3x-7)

=> 20x-60x+45-2x²-14x+3x+7

=> 18x² - 71x + 52

 

2) 5(4x²-12x+9)

2013-03-11T19:14:14+01:00

1. C= 20x²-60x+45-(2x-3)(x+7)

    C= 20x²-60x+45-(2x²+14x-3x-21)

    C= 20x²-60x+45-2x²-14x+3x+21

    C= 18x²-71x+66