They are supplementary angles
I would answer the problem but first upload the diagram
8^2 and 9^2. Because 8 squared equals 64 and 9 squared equals 81
Since this is a parallelogram, both bases are equal. You can set them equal to each other to find x:
6+3x=x+14
Subtract x from both sides.
6+2x=14
Subtract 6 from both sides.
2x=8
Divide by 2.
x=4
Hope this helps! :)