S'il vous plaît aidez moi 1°) Réduis les expressions suivantes : A = 4x−3−3x+4 B = −3x+2+x−5 C = −9x+x−8+5x D = 2−2x−4x+4−x 2°) Calcule chacune des expressions

Bonjour ,

1.

A = 4x−3−3x+4

= 4x-3x-3+4

=1x+1

B = −3x+2+x−5

= -3x+x+2-5

= -2x-3

C = −9x+x−8+5x

= -9x+x+5x-8

= 15x-8

D = 2−2x−4x+4−x

= 2x-4x-x+2+4

= -7x+6

2 .

Il faut remplacer les x par 3 :

Exemples :

A = 4x−3−3x+4

= 4×3-3-3×3+4

= 4×3-3×3-3+4

= 12-9+1

= 4

B = −3x+2+x−5

= -3×3+2+3-5

= -9-0

= -9

C = −9x+x−8+5x

= -9×3+3-8+5×3

= -9×3+5×3+3-8

= -27+15-5

= -17

D = 2−2x−4x+4−x

= 2-2×3-4×3+4-3

= -2×3-4×3+2+4-3

= -6-12+3

= -15

Bonjour,

A = 4x−3−3x+4

= x +1

B = −3x+2+x−5

= -2x -3

C = −9x+x−8+5x

-3x -8

D = 2−2x−4x+4−x

-7x +2

x= 3

x +1 -> 3+1= 4

-2x -3 -> -2*3 -3 = -6 -3 = -9

-3x -8 -> -3*3 -8 = -17

-7x +2 -> -7*3 +2 = -19