document.write( "Question 1039558: Which expression is equivalent to 2x^2-2x+7\r
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\n" ); document.write( "c) (4x^2-6x+11)+(2x^2-4x+4)
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Algebra.Com's Answer #654320 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "The easiest way to tell which is the answer is to quickly \r\n" );
document.write( "mentally substitute x=0 in 2x^2-2x+7, which easily gives +7.\r\n" );
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document.write( "Then we quickly mentally substituting x=0 in each of the choices:\r\n" );
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document.write( "a) (4x+12)+(2x^2-6x+5)\r\n" );
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document.write( "Substituting x=0 mentally in that gives 12+5 or 17, thus it\r\n" );
document.write( "cannot be the correct choice.\r\n" );
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document.write( "b) (x^2-5x+13)+(x^2+3x-6)\r\n" );
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document.write( "Substituting x=0 mentally in that gives 13-6 or +7, thus it\r\n" );
document.write( "is a possible choice.\r\n" );
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document.write( "c) (4x^2-6x+11)+(2x^2-4x+4)\r\n" );
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document.write( "Substituting x=0 mentally in that gives 11+4 or 15, thus it\r\n" );
document.write( "cannot be the correct choice.\r\n" );
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document.write( "d) (5x^2-8x+120)+(-3x^2+10x-13)\r\n" );
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document.write( "Substituting x=0 mentally in that gives 120-13 or 107, thus it\r\n" );
document.write( "cannot be the correct choice.\r\n" );
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document.write( "So the answer is (b), the only one that gave +7 when 0 was\r\n" );
document.write( "mentally substituted for x.  This is much easier than simplifying\r\n" );
document.write( "each one to see which simplifies to the same.  If more than one\r\n" );
document.write( "choice had given +7 when x was substituted for x, I would then \r\n" );
document.write( "have also mentally substituted x=1 in those.\r\n" );
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document.write( "Edwin
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