Answer:
Decreased by 20%
Step-by-step explanation:
Just add the 10%+10% to get the answer.
Answer: C. 
Step-by-step explanation:
1. You have the following equation of the parabola in Vertex form:

Where h is the x-coordinate of the vextex and k is the y-coordinate of the vextex.
2. You know that the vertex of this parabola is at (-2, 5), then, susbtitute this point into the equation. Then, you obtain:

3. Therefore, the answer is the option C.
They are functions because they have the variables
-they can get the same answer