Answer:
'''A ray has one endpoint and extends indefinitely in one direction. A pair of opposite rays are two rays that have the same endpoint and extend in opposite directions. Rays are always named with two points and the first point in the name must be the endpoint.'''
What Do you need help with if you added a picture we cant see it
1. Perfect square trinomials, are 2nd degree polynomials, of the form

so that

, which can be written as perfect squares.
2. For example

3. Thus

are perfect square trinomials.
4.

5. In the first case -b=20, so b=-20. In the second case, -b=-20, so b=20.
6. b∈{-20, 20}