From googling linear pair you we now that both angles add to 180.
2x + (2y - 10) = 180
You are missing out information since there are two unknowns, x and y. To solve two unknowns we need to equations. If you would like to comment what the other equation could be i.e. there could be another 'linear pair' rule that I don't know about - which is likely - I'd reply and solve it better for you.
The airplane is ascending from it previous destination and then descending to its next destination, making its speed decline and remain the same.
