document.write( "Question 1210391: The sum of two numbers is 21.five times the first number added to 2 times the second number is 66.find the numbers \n" ); document.write( "

Algebra.Com's Answer #852174 by Edwin McCravy(20055) $\"\"$ $\"About$

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document.write( "The sum of two numbers,\r\n" );
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document.write( "x = first number\r\n" );
document.write( "y = second number\r\n" );
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document.write( "is 21.\r\n" );
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document.write( "So x + y = 21\r\n" );
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document.write( "five times the first number added to 2 times the second number is 66.\r\n" );
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document.write( "5x + 2y = 66\r\n" );
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document.write( "Solve the first equation for y:  y = 21 - x.\r\n" );
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document.write( "Substitute in the second equation:\r\n" );
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document.write( "5x + 2(21 - x) = 66\r\n" );
document.write( "5x + 42 - 2x = 66\r\n" );
document.write( "3x = 66 - 42\r\n" );
document.write( "3x = 24\r\n" );
document.write( " x = 8\r\n" );
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document.write( "y = 21 - (8)\r\n" );
document.write( "y = 13\r\n" );
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document.write( "Answer: The first number is 8 and the second number is 13.\r\n" );
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document.write( "Yes, I know it can be done with only one unknown.  But I think it's \r\n" );
document.write( "much easier when students can think of each single number mentioned \r\n" );
document.write( "in the word problem as represented by one single letter, than it is \r\n" );
document.write( "to have to think of the second number as the complicated combination \r\n" );
document.write( "of a number, a sign, and an expression in the letter used for the \r\n" );
document.write( "first number. \r\n" );
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document.write( "Edwin

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