D) perpendicular!
A perpendicular's definition is: a straight line at an angle of 90° to a given line, plane, or surface.
And if you mark them on a graph you could see these two are opposite of each other.

Explanation:
Since we have given that
Speed at which Eugene walked all the way to school = 3 mph
After realizing that she forgot her math book, she ran back
Speed at which Eugene walked back to her house = 7 mph
Let the distance between her house and her school be x
According to question,

Hence,

1. 51
2. 34
3. 95
4. 38
5. 47
6. 74
7. 59
I hope this helps!!
Answer:
Step-by-step explanation:
Definition: A letter that is placed in an unknown number place.
Example: 8+B+9
The variable would be B.
Converse I think but I’m not sure