Answer:
(10, 1)
Explanation:
-x = -y - 9 has already been solved for -x. Multiply every term of this equation by -1 to obtain x = y + 9.
Now substitute y + 9 for x in the first equation. We get:
(y + 9) + y = 11, or, after combining the y terms, 2y = 2.
Solving for y, we get y = 1.
Subbing 1 for y in the first equation results in: x + 1 = 11.
This yields x = 10.
Thus, the solution is (10, 1).