Aidez moi pour l'exercice n°9,n°10 et n°11

9) -3 (3+2 petit 4) / 2² * 5 -14
   = -3 +16 / 4*5 -14
   = 13 / 20 -14
   = 13 / 6
   = 13 / 6 ou 2,2

11) a)  x= -1
2*(-1)² -5 * (-1) +3
= 2 +5 +3
= 10

b) 4x - (3x +5)
= 4x -3x -5
= x -5

-7x +6 ( x +2)
= -7x +6 +x +2
= -6x +8

5 - (1 -2x) + (2x +5)
= 5 -1 +2x +2x +5
= 4x +9

c) (1 +3x) (7 +5x)
= 7 +5x +21x +15x²
= 7 +26x +15x²

(-6 +x) (3-x)
= -18 +6x +3x -x²
= -18 +9x -x²

(x +3) (2x -4) -3 ( 4x -1)
= 2x² -4x +6x -12 -12x +3
= 2x² -10x -9

d)  x+7= -2
  x +7 -7= -2 -7
 x= -9

-x -4= 7
-x -4 +4= 7+4
x= 11

x/-3= 72
x/-3* 3= 72*3
x= 216

2x +1= -4
2x +1 -1= -4 -1
2x= -5
2x/2= -5/2
x= -5/2 ou -2,5 (cest pareil)

2 (x -3) = 11
2x -6= 11
2x -6 +6= 11 +6
2x= 17
2x/2= 17/2
x= 17/2 ou 8,5 (cest pareil)

Bonjour

9.
A = 3(3+2^4)  / 2² x 5 - 14
A = 3(3 + 16) / 4 x 5 - 14
A = 3(19) / 20 - 14
A = 3 x 19 / 6
A = 57 / 6
A = 19 / 2

10.
B = (3 x 10^5 x 4 x (10^-3)^2)) / 16 x 10^-4
B = (3 x 4)/16   x   (10^5 x (10^-3)^2)/ 10^-4
B = 12/16    x   10^(5-6+4)
B = 3/4   x 10^3
B = 0,75 x 10^3
B = 7,5 x 10^2


11.
a) si x =  -1                l'expression 2² - 5x + 3 donne:
2(-1)² - 5(-1) + 3 = 2 + 5 + 3 = 10

b)
1) 4x - (3x + 5) = 4x - 3x - 5 = x - 5 
2) -7x + 6(x+2) = -7x +6x + 12 = -x + 12
3) 5 - (1-2x) + (2x+5) = 5 - 1 + 2x + 2x + 5 = 4x + 9

c) Développons et réduisons
1) (1+3x)(7+5x) = 7 + 5x + 21x + 15x² = 15x² + 26x + 7
2) (-6+x)(3-x) = -18 + 6x + 3x - x² = -x² + 9x - 18
3) (x+3)(2x-4) - 3(4x-1) = (2x² - 4x + 6x - 12) - (12x - 3)
= 2x² - 4x + 6x - 12 - 12x + 3 = 2x² - 10x - 9

d)
x+7 = -2
    x = -7-2
    x = -9

S = {-9}

-x-4 = 7
    -x = 7 + 4
    -x = 11
     x = -11

x/-3 = 72
    x = (-3) x 72
    x = -216


2x+1 = -4
     2x = -4-1
       x = -5/2

2(x-3) = 11
  2x-6 = 11
      2x = 11 + 6
        x = 17/2