Relax

Respuesta :

I know I'm definitely wrong: 540. it looks like a right angle. 
I did on the calculator:
18 * 90 = 1620
1620 / 3 = 540
X=23

3x+18+93=180
3x+111=180
-111 -111
3x=69
3x/3=69/3
X=23