The teacher will be very surprised to see your correct solution 😉
6*x 253 37*x
-18 - --- = --- + ----
5 5 10
-18-(6/5)*x = (253/5)+(37/10)*x
-18-6/5x = (253/5)+(37/10)*x
-18-6/5x = 253/5+37/10x
x = 343/5 / (-49/10)