Réponses

2013-01-15T17:02:50+01:00

(x-2)^2-(x-1)(x+4)

(x-2)(x-2)-(x-1)(x+4)

(x^2-2x-2x+4)-(x^2+4x-x-4)

(x^2-4x+4)-(x^2+3x-4)

x^2-4x+4-x^2-3x+4

x^2-x^2-4x-3x+4+4

0-7x+8

7x+8

2013-01-15T17:04:06+01:00

(x-2)² - (x-1) (x+4).

=x²-4x+4-(x²+4x-x-4)

=x²-4x+4-x²-4x+x+4

=-7x+8