Answer:
19=x or x+19 (however your tracher or you prefers it)
Explanation:
5+10=x-4 (isolate x)
+4 to both sides (cancels 4 on one side to isolate x)
then you'll have either 10+4 or 5+4 (doesn't matter just what ever is convienient to you)
then you will have 19=x (when you add everything)