I think it is D:{5,-infinity}
Answer:

Step-by-step explanation:
Given that:
Distance traveled by seal to catch the fish = 15 below sea level
Sea lion wanted to catch a larger fish so sea lion dove 6 feet lesser than two time the distance that the seal traveled.
To find:
The expression to represent the position of the sea lion in the sea.
Solution:
If the distance traveled by seal is represented by
then as per the question statement:
Twice of
= 
6 lesser than twice of
=
- 6
Now, putting the value of
= 15
Therefore, the expression to represent the sea lion's position w.r.to sea level.

Answer:
First figure is regular and convex.
Second figure is irregular and convex.
Step-by-step explanation:
Here given 2 polygons we have to classify these whether these are convex, concave, regular and irregular.
Regular Polygon is the polygon which have all sides and all angles equal.
Convex Polygon is the polygon in which measure of all interior angles less than 180° and if measure of each of interior angle greater than 180° then it is concave.
In the first figure, all sides are equal therefore and each of interior angle of polygon is less than 180°. Hence, the polygon is regular and convex.
In the second figure, all sides are not equal and each of interior angle of polygon is less than 180°. Hence, the polygon is irregular and convex.