x-5=3 _ x = 5 + 3 = 8
x+8= -12 _ x = -12-8= -20
4x = 36 _ x = 36/4 = 9
x/8 = 15 _ x = 15*8 = 120
5x-3 = 12 _ 5x = 15 _ x = 3
4 + 5x = 8 _ 5x = 4 _ x = 4/5
-3x + 1 = 19 _ -3x = 18 _ x = -6
-3 + 5x = 12 + 2x _ 5x-2x = 12 + 3 _ 3x = 15 _ x=5
7-x = 3x - 3 _ 7+3 = 3x + x _ 10 = 4x _ x = 10/4
x^2 = 16, x = -4 ou 4
Voilà, n'hésite pas si t'as des questions
