Answer:
<DEB= 125 degrees
Explanation:
To get this, you would need to know all 2 angles of the triangle.
To find the first angle, simply do 180-107 to get 73(because supplementary angles add up to 180 degrees).
Next, 180-52(given angle)-73 to get 55 because the 3 angles of a triangle add up to 180(triangle angle sum theory).
You would see that <DEB is part of another supplementary angle so, do 180-55 to get 125.
<DEB=125 degrees.