Sagot :
Bonjour
Supprimer les parenthèses et réduire.
a. (3x + 5) + (4x - 2)
= 3x + 5 + 4x - 2
= 3x + 4x + 5 - 2
= 7x + 3
b. (10x + 3) -(4x + 8)
= 10x + 3 - 4x - 8
= 10x - 4x + 3 - 8
= 6x - 5
c. (-9x + 1) +(4 - 5x)
= - 9x + 1 + 4 - 5x
= - 9x - 5x + 1 + 4
= - 14x + 5
d. (x-7) - (4x - 3)
= x - 7 - 4x + 3
= x - 4x - 7 + 3
= - 3x - 4
62 il soit A = 8x - 6 et B = -5x + 4.
1. Donner la forme réduite, en fonction de x.
a. A + B
8x - 6 - 5x + 4 = 3x - 2
b. A - B
8x - 6 - ( -5x + 4) = 8x - 6 + 5x - 4 = 13x - 10
c. 2A + 3B
2 (8x - 6 ) + 3 ( -5x + 4)
= 16x - 12 - 15x + 12 = x
d. 5A - 3B
5 (8x - 6) - 3 ( -5x + 4)
= 40x - 30 + 15x - 12
= 55x - 42
2. À l'aide de deux méthodes différentes, déterminer la forme développée et réduite de 2(A + B).
2 (8x - 6 - 5x + 4)
= 2 (3x - 2)
= 6x - 4
et
2 (8x - 6 - 5x + 4)
= 16x - 12 - 10x + 8
= 6x - 4.
61/
a) =3x +5 +4x -2
=7x + 3
b)
=10x + 3 - 4x -8
= 6x -5
c) = -9x + 1 +4 -5x
= -14x +5
d) x-7-4x+3
= -3x - 4
62.
1/ a) 8x-6 + (-5x+4)
= 8x -6 -5x +4
= 3x -2
b) 8x-6 - (-5x+4)
= 8x-5 + 5x +4
= 13x -1
c) 2(8x-6) + 3(-5x+4)
=16x - 12 - 15x + 12
= x
d) 5(8x-6) - 3(-5x+4)
= 40x - 30 + 15x - 12
= 55x - 42
2/
1er méthode:
2(A + B)
= 2(8x-6 + (-5x+4))
= 2(8x-6-5x + 4)
= 2( 3x -2)
= 6x-4
2ème méthode :
2(A+B)
= 2(8x-6) + 2(-5x+4)
= 16x-12 + (-10x) +8
= 16x -12 -10x +8
= 6x - 4
a) =3x +5 +4x -2
=7x + 3
b)
=10x + 3 - 4x -8
= 6x -5
c) = -9x + 1 +4 -5x
= -14x +5
d) x-7-4x+3
= -3x - 4
62.
1/ a) 8x-6 + (-5x+4)
= 8x -6 -5x +4
= 3x -2
b) 8x-6 - (-5x+4)
= 8x-5 + 5x +4
= 13x -1
c) 2(8x-6) + 3(-5x+4)
=16x - 12 - 15x + 12
= x
d) 5(8x-6) - 3(-5x+4)
= 40x - 30 + 15x - 12
= 55x - 42
2/
1er méthode:
2(A + B)
= 2(8x-6 + (-5x+4))
= 2(8x-6-5x + 4)
= 2( 3x -2)
= 6x-4
2ème méthode :
2(A+B)
= 2(8x-6) + 2(-5x+4)
= 16x-12 + (-10x) +8
= 16x -12 -10x +8
= 6x - 4