Update HOME_EXAM_Type_check_part2.md

HOME_EXAM_Type_check_part2.md

@@ -70,7 +70,7 @@ or
 ```
 
 Not equals (!=):
-math```
+```math
 \frac{\Gamma \ \vdash \ e1 \ : \ bool \quad \Gamma \ \vdash \ e2 \ : \ bool}{\Gamma \ \vdash (e1 \ != \ e2) \ : \ bool}
 ```