bonjour
exercice 4
a)
4x= 3/5 =>
x = 3 / 5×4
x = 3/20
b)
(2/3) x = 7
2x = 7×3
2x = 21
x = 21/2
c)
(6/5)x = -7/11
6x = -7×5 /
11 = -35/11
x = -35/11×6
x = -35/66
d)
-7x = 4/-3
x = 4 /
-3×-7 =>
x = 4/ 21
e)
(-3/2) x = 5 => -3x = 2×5 =>
-3x = 10 => 3x = -10
x = -10/3
f)
(-5/7) x = -2/-3
-5x = -2×7
/-3 = -14/-3
x = -14/ -5×-3
x = -14/15
exercice 5
a)
2x = 6
x = 6/2
x=3
b)
3x = 33
x = 33/3
x = 11
c)
x-9 = 4
x = 4+9
x = 13
d)
2x +6=0
2 x=-6
x=-6/2
x= -3
e)
3x - 6 =9
3x = 9+6
3x =15
x=15/3
x=5
f)
5x+2=x
5x-x=-2
4x=-2
x=-2/4
x=-1/2
g)
2 ×(x+3) = x
2x+6=x
2x-x = -6
x = -6
h)
(x+6) = 3 ×(x+1)
x+6 = 3x+3
6-3 = 3x -x
3 = 2x
x = 3/2
