document.write( "Question 1062842: Which of the following equations does not define y as a function of x?
\n" ); document.write( "A. xy^2 = 8
\n" ); document.write( "B. x^2 + y^2 = 0
\n" ); document.write( "C. 3y = 7
\n" ); document.write( "D. y = square root of x - 3
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Algebra.Com's Answer #677840 by Edwin McCravy(20060) $\"\"$ $\"About$

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Which of the following equations does not define y as a function of x?
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document.write( "Solve for y by dividing both sides by x, (where x is not 0)\r\n" );
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document.write( "That does not define a function because there is NOT just \r\n" );
document.write( "ONE y for each x, since there are TWO y's for each x.\r\n" );
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document.write( "For example when x = 2,\r\n" );
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document.write( "This is not a function because, for example, when x = 2, there are\r\n" );
document.write( "TWO values for y, +2 and -2.  So that's why it doesn't define a function.\r\n" );
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\n" ); document.write( "B. x^2 + y^2 = 0
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document.write( "There is only one ordered pair that satisfies that.\r\n" );
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document.write( "That is (x,y) = (0,0)\r\n" );
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document.write( "It does define a function whose domain is {0} and whose range is {0}\r\n" );
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document.write( "It defines a function because there is just one y, 0, for each x, 0,\r\n" );
document.write( "since the only x and y are both 0.\r\n" );
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document.write( "So, it's a function because there is just one y for every x.\r\n" );
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\n" ); document.write( "C. 3y = 7
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document.write( "    y = 7/x\r\n" );
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document.write( "That defines a function because there is just one y for each x.\r\n" );
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\n" ); document.write( "D. y = square root of x - 3
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document.write( "That defines a function because there is just one y for each x.\r\n" );
document.write( "Edwin

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