Bonsoir,
a)
3x+2 +x +3 + 2x+1
= 6x +6
b)
6x+6 = 18
6x = 18 -6
6x = 12
x= 12/6
x= 2
c)
BA = 3x+2 = 8
AC = x+3 = 5
BC = 2x+1 = 5
BC = AC
=> c'est un triangle isocèle
