347 and 865.
To solve this problem you set up two equations,
x+y=1212 and x-y=518.
You then get the second x by itself by adding y to both sides.
You then have x+y=1212 and x=y+518.
After this you substitute the x into the first equation and have y+518+y=1212.
Then simplify to 2y=694 and y=347
Now that y=347 you put it in the original equation. Solve and get that x=865
