Répondre :
1.
2x+3=0
2x=-3
x=-3/2
x=-1.5
2.
x/6+5=0
x/6+30/6=0
x+30=0
x=-30
3.
-4x+15=8x
-4x-8x=-15
-12x=-15
x=15/12
4.
8x+9=5x-6
8x-5x=-6-9
3x=-15
x=-15/3
x=-5
5.
5(x+9)=50
5*x+5*9=50
5x+45=50
5x=50-45
5x=5
x=5/5
x=1
6.
2x/3+2=-3
2x/3+6/3=-9/3
2x+6=-9
2x=-9-6
2x=-15
x=-15/2
x=-7.5
7.
7(x+9) = 3(x-2)
7*x+7*9=3*x+3*(-2)
7x+63=3x-6
7x-3x=-6-63
4x=-69
x=-69/4
x=-17.25
1) 2x + 3 = 0
2x = -3
x = -3/2 ( équivalent à 1,5 )
2) x/6 + 5 = 0
x/6 + 5x6/1x6 = 0
x/6 + 30/6 = 0
x + 30 = 0
x = -30
3) -4x +15 = 8x
15 = 8x + 4x
15 = 12x
15/12 = x
x = 5/4
4) 8x + 9 = 5x - 6
8x - 5x = -6 -9
3x = -15
x = -15/3
x = -5
5) 5(x+9) = 50
5x + 45 = 50
5x = 50 - 45
5x = 5
x = 5/5
x = 1
6) 2x/3 +2 = -3
2x/3 +2x3/1x3 = -3x3/1x3
2x +6 = -9
2x = -9 -6
2x = -15
x = -15/2
7) 7(x+9) = 3(x-2)
7x +63 = 3x -6
7x -3x = -6 -63
4x = -69
x = -69/4