document.write( "Question 389639: Find two numbers whose sum is 17 and whose squares total 145 \n" ); document.write( "
Algebra.Com's Answer #276152 by richard1234(7193)\"\" \"About 
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The easiest way is probably to guess and check, since it is likely that both numbers will be integers. Guessing and checking, the numbers are 9 and 8.\r
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\n" ); document.write( "\n" ); document.write( "Or, we can use \"p+%2B+q+=+17\" and \"p%5E2+%2B+q%5E2\" = 145. Squaring the first equation,\r
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\n" ); document.write( "\n" ); document.write( "\"%28p+%2B+q%29%5E2+=+p%5E2+%2B+2pq+%2B+q%5E2+=+289\" --> \"2pq+=+144\" --> \"pq+=+72\".\r
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\n" ); document.write( "\n" ); document.write( "If we assume that p and q are roots of a polynomial \"x%5E2+%2B+bx+%2B+c\", use Vieta's formula:\r
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\n" ); document.write( "\n" ); document.write( "The sum of the roots is -b --> \"p+%2B+q+=+17+=+-b\"
\n" ); document.write( "The product of the roots is c --> \"pq+=+72+=+c\"\r
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\n" ); document.write( "\n" ); document.write( "This implies b = -17 and c = 72, so p and q are roots of the polynomial \"x%5E2+-+17x+%2B+72\". The polynomial can be factored as \"%28x+-+8%29%28x+-+9%29\" so p,q = (8,9).
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