Réponses

2014-01-24T20:09:42+01:00
1) -7 (x-1) = - 7x + 7

2) x (2x+10) = 2x² + 10x

3) 3x (-2 - x ) = -6x - 3 x²

4) -4 x (2x + 1) = -8x² - 4x
2014-01-24T20:14:40+01:00
-7 (x-1)
= -7x - 7* (-1)
= -7x + 7

x (2x + 10)
= 2x² + 10x

3x (-2 - x )
= 3x*(-2 ) - 3x²
= -6x - 3x²

-4 x (2x + 1)

=-4x * 2x - 4x

= -8x² -4x