Bonjour,
x + 4 = 1
x = 1 - 4
x = -3
x - 2 = - 1
x = - 1 + 2
x = 1
-5x = 4
x = -4/5
-4 * 2 = -8
-8 + 3 = -5
5 * 2 = 10
10 + 3 = 13
x * 2 = 2x
2x + 3