Bonsoir,
Il suffit de faire passer les x à gauche et les nombres entiers à droite
a)
3x + 5 = 4x - 7
3x = 4x - 7 - 5
3x - 4x = -12
-x = -12
x = 12
b)
2x - 9 = 8x + 3
2x = 8x + 3 + 9
-6x = 12
-x = 2
x = -2
c)
-2x + 3 = 3x - 1
-2x = 3x - 1 - 3
-2x - 3x = -4
-5x = -4
-x = -4/5
x = 4/5
d)
5 - 2x = x
-3x = -5
x = 5/3
e)
1 + (3/10)x = 4 - (2/5)x
(3/10)x = 3 - (2/5)x
(3/10)x + (2/5)x = 3
(3/10)x + (4/10)x = 3
(7/10)x = 3
x = 3/(7/10)
x = 3 × 10/7
x = 30/7
f)
x^7 + 3x - 2 = 7x + 4 + x^7
3x - 2 = 7x + 4
-4x = 6
-x = 6/4
x = -6/4
