Respuesta :
3c+-9=18
+-=-
3c-9=18
move 9c to the other side and the sign changes from negative to positive.
3c-9+9= 18+9
3c= 27
Divide by 3
c=9
3c+-9=18
+-=-
3c-9=18
move 9c to the other side and the sign changes from negative to positive.
3c-9+9= 18+9
3c= 27
Divide by 3
c=9