Answer:
x= -2; y= -2
Explanation:
The opposite sides of a parallelogram are congruent, and therefore we can make two observations:
9=-9x-9
19=-10y-1
Then we can just solve each of the equations to get x and y:
9 = -9x - 9
+ 9 +9
18=-9x
----------
-9
-2=x
19=-10y-1
+1 +1
20=-10y
------------
-10
-2=y