Bonjour,
a)
8x -10 = 4+x
8x-4x = 4+10
4x = 14
x= 14/4 =3,5
=> faux
b)
2x+16 +3 = 4-3x
2x+3x = 4-16 -3
5x = -15
x= -15/5 = -3
=> vrai
c)
12x-1 = 10x -10 +1
12x -10x = -10 +1 +1
2x = -8
x= -8/2 = -4
d)
x² -6x +9 = x² -5x
x² -x² -6x +5x = -9
-x =-9
x = 9
