Why is this NOT a function?

What is, because every input doesn't have only one output (ex: -2 has 2 outputs)?
Identify the MAXIMUM:

What is 8?
Using the graph below, find and interpret the value of D(3) in context.
What is "after 3 minutes, you are 400 meters from home"?
Graph the piecewise function:

What is...>
Lynn has a hairstyle with bangs. Lynn usually has her bangs trimmed every three months. The graph at the shows the growth of her bangs over the past year.
What is the RANGE?
What is 2≤y<8?
Which of the following relations DO represent functions? 
What is relation A and D?
Find the INCREASING INTERVAL:

What is 0<x<2?
How long did it take Juan to finish the 4 mile race? Include units!
What is 13 minutes?
Fill in the boxes for the piecewise function graphed below:
What is -2 (box 1) and 3 (box 2)?
Identify the MAXIMUM: 
What is NONE?
Given f(x)=2x-5 , find f(-3) .
What is
f(-3)=-11?
Identify the RANGE (use appropriate notation):

What is
0<=y<\infty ?
How much time had passed when Juan and Antonio were the same distance from the starting line? 
What is 7 minutes?
Given the graph of h(x), evaluate h(-2) and h(0):
What is 1 and 9?
Find the MAXIMUM:

What is 5?
Use the table below to find x given g(x)=-2 .

What is
x=-1?
Identify the DOMAIN (use appropriate notation):

What is -5<x<=5 ?
Which story matches the graph: 

What is C?
Identify the DOMAIN AND RANGE of the piecewise function graphed below (use appropriate notation):

What is -\infty<x<\infty (domain) and -1<=y<\infty (range)?
Identify the DOMAIN AND RANGE (use appropriate notation):

What is -6<=x<8 and -7<=y<=9 ?
Given k(x)=-3x+1 , find x if k(x)=10 .
What is
x=-3.
Identify the DECREASING INTERVAL(S) (use appropriate notation):

What is 1<x<\infty ?
Below is a graph showing Ariel's hiking elevation as a function of time.
What elevation above sea level is Ariel at when he begins his hike? Include units.

What is 5 ft?
Graph the piecewise function:
What is...?

Identify the DOMAIN AND RANGE (use appropriate notation):

What is -7<=x<7 and -8<y<=8 ?