Bonjour,j'ai besoin d'aide pour mon dm de maths (niveau 4eme)s'il vous plait( vous trouverais ci-joint les exo .)
ps: il faut détailler les étapes
a) 4x+5=3x-2
4x-3x = -2 -5
x = -7
b) 7x-6 = 3x+7
7x -3x=7+6
4x=13
x= 13/4
c) 5x-3 = 7x +9
5x - 7x = 9 +3
-2x=12
x= -2/12 = -1/6
d) 12x-7= 15x+2
12x-15x=2+7
-3x = 9
x= -3/9 = -1/3
a) 7x-8=3x+6
7x-3x=6+8
4x = 14
x=14/4 = 7/2
b) 3x-2 = 5x+3
3x-5x = 3+2
-2x=5
x=-5/2
c) 3x-5 = 8x-11
3x-8x = 11+5
-5x=16
x= -5/16
d) 7x+7 = 9x-3
7x-9x=-3-7
-3x = -4
x= -3/-4 = 3/4
a) 17x-8 = -7x-2 b) -4x-21 = 3x+7
17x+7x=-2+8 -4x-3x=7+21
24x= 6 -7x= 28
x = 6/24 = 1/4 x= -28/7 = -4
c) -3x+11 = -8x-9 7x+3 = -9x-7
-3x + 8x = -9-11 7x+9x = -7-3
5x=-20 16x = -10
x= -20/5 = -4 x=-10/16
a) 7 X (2x-1) = 8x +5 b) 8a - 2 = 3 X (4a-5)
14x -7 = 8x+5 8a - 2 = 12a-15
14x-8x = 5+7 8a-12a = -15+2
6x=12 -4a = -13
x=12/6 = 2 a= -13/-4 = 13/4
c) 2 X (3b + 7) = 5 X (-2b +1) d) 3 X (-1 -2t) = 4 X (1 - 5t)
6b + 14 = -10b+5 -3-6t = 4-20t
6b+10b = 5-14 -6t+20t = 4+3
16b = -9 14t = 7
b=-9/16 t= 7/14 = 1/2