document.write( "Question 1197773: {(6, -6), (2, 2), (0, 8), (5, 2), (-5, 2)}\r
\n" ); document.write( "\n" ); document.write( "Is the relation a function?\r
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\n" ); document.write( "{(8, -8), (-4, -8), (7, -1), (-7, -1)}\r
\n" ); document.write( "\n" ); document.write( "Is the relation a function?\r
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\n" ); document.write( "{(-24, -141), (-9, -141), (133, -83), (-21, -83), (-9, -141), (133, -138)}\r
\n" ); document.write( "\n" ); document.write( "Is the relation a function? \n" ); document.write( "
Algebra.Com's Answer #831172 by math_tutor2020(3817)\"\" \"About 
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\n" ); document.write( "Answers:
  1. Yes it's a function
  2. Yes it's a function
  3. No, it's not a function

\n" ); document.write( "Explanation:
  1. We have a function since none of the x coordinates repeat themselves. Each x input leads to exactly one output.
  2. Similar reasoning as problem 1.
  3. The input x = 133 repeats itself. The input x = 133 leads to more than one output (y = -83 and y = -138). This is why we don't have a function. You can toss out or ignore the duplicate copy of (-9, -141)
As a visual alternative, you can use the vertical line test to see if you have a function or not.
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