Réponses

2014-02-28T16:20:58+01:00
E= (2x+5)(x-7)+5x(2-x)
   = (2x²-14x+5x-35) + 10x-5x²
   = 2x²-9x-35+10x-5x²
   = -3x² +x -35

Pour x=-1, on a :

-3 * (-1)² + (-1) -35
= -3-36
=-39
2014-02-28T16:23:56+01:00
Bonjour
e=(2x+5)(x-7)+5x (2-x)
e:=2x^2-14x+5x-35+10x-5x^2
e=-3x^2+x-35

e (-1)=-3 (-1)^2+(-1)-35
e (-1)=-3-1-35
e (-1)=-39