Question 255172
(-2, 7), (-1, 5), (0, 3), (1, 1), (2, 1) is this a function and if so why
<pre><font size = 4 color = "indigo"><b>
It is a function because all the x-coordinates (first coordinates)
are different.  It means that if they were plotted on a graph no 
point is directly above or below any other point.

{{{drawing(400,400,-3,3,-1,8, graph(400,400,-3,3,-1,8),
locate(-2, 7,"(-2,7)"), locate(-1, 5,"(-1,5)"), locate(0,3,"(0,3)"), locate(1, 1,"(1,1)"), locate(2, 1,"(2,1)"),

line(-2+.1, 7,-2-.1,7),line(-2, 7+.1,-2,7-.1),line(-2+.1, 7+.1,-2-.1,7-.1),line(-2+.1, 7-.1,-2-.1,7+.1),
line(-1+.1, 5,-1-.1,5),line(-1, 5+.1,-1,5-.1), line(-1+.1, 5+.1,-1-.1,5-.1), line(-1+.1, 5-.1,-1,5+.1)    ,

 line(0+.1, 3,0-.1,3), line(0, 3+.1,0,3-.1),line(0+.1, 3+.1,0-.1,3-.1),
line(0+.1, 3-.1,0-.1,3+.1),

 line(1+.1, 1,1-.1,1), line(1,1+.1,1,1-.1), line(1+.1,1+.1,1-.1,1-.1), line(1+.1,1-.1,1-.1,1+.1)  , 

 line(2+.1, 1,2-.1,1), line(2,1+.1,2,1-.1), line(2+.1,1+.1,2-.1,1-.1),
 line(2+.1,1-.1,2-.1,1+.1)  )}}}

Edwin</pre>