I would solve for x: .
Then replace x by that in the second equation:
(You have "+11" but without an "=" there is no equation so I assume you mean "=".)
Now isolate the square root, , and square both sides: .
Again, isolate the square root, and square both sides.
That is a fourth degree polynomial equaton which might be difficult to solve. The only possible rational roots are the factors of 196 so I would recommend trying those first.