document.write( "Question 360239: For a certain 3-digit number, interchanging the first and last digits gives a 3-digit number 297 less than the original number. Doubling the first and last digits of the original number gives a 3-digit number and increases the sum of the digits to 15 what is the number? \n" ); document.write( "
Algebra.Com's Answer #257062 by ankor@dixie-net.com(22740)\"\" \"About 
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Let 100x + 10y + z = a three digit number
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\n" ); document.write( "Write an equation for each statement:
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\n" ); document.write( "For a certain 3-digit number, interchanging the first and last digits gives
\n" ); document.write( " a 3-digit number 297 less than the original number.
\n" ); document.write( "100x + 10y + z = 100z + 10y + x + 297
\n" ); document.write( "100x - x + 10y - 10y = 100z - z + 297
\n" ); document.write( "99x = 99z + 297
\n" ); document.write( "Simplify, divide thru by 99
\n" ); document.write( "x = z + 3
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\n" ); document.write( "Doubling the first and last digits of the original number gives a 3-digit
\n" ); document.write( " number and increases the sum of the digits to 15
\n" ); document.write( "2x + y + 2z = 15
\n" ); document.write( "Replace x with (z+3)
\n" ); document.write( "2(z+3) + y + 2z = 15
\n" ); document.write( "2z + 6 + y + 2z = 15
\n" ); document.write( "4z + y = 15 - 6
\n" ); document.write( "4z + y = 9
\n" ); document.write( "y = -4z + 9
\n" ); document.write( "only two positive integer solutions here
\n" ); document.write( "z=1, y=5, then x=4
\n" ); document.write( "451 is the number
\n" ); document.write( "and
\n" ); document.write( "z=2, y=1, then x=5
\n" ); document.write( "512 is the number, however, it says:
\n" ); document.write( "\"Doubling the first and last digits gives a 3-digit number\", so it can,t be 512
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\n" ); document.write( " what is the number? 451
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\n" ); document.write( "Check:
\n" ); document.write( "451 - 154 = 297
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