document.write( "Question 705702: two numbers differ by 8, their product is 65,what is the number? \n" ); document.write( "
Algebra.Com's Answer #434728 by josgarithmetic(39618)\"\" \"About 
You can put this solution on YOUR website!
Some may quickly recognize that as a product, and being a factor of 5, 13*5=65, which we may also recognize as 12*5 plus one more 5. Basic addition fact may be in some people's heads and 8+5=13 is immediately recognized. \r
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\n" ); document.write( "\n" ); document.write( "You ask for \"what's the number\", but the description indicates TWO numbers. I see 13 and 5. \r
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\n" ); document.write( "\n" ); document.write( "You probably want an algebraic arithmetic treatment so here it is.\r
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\n" ); document.write( "\n" ); document.write( "Numbers m and n.
\n" ); document.write( "Differ by 8: n-m=8
\n" ); document.write( "Product is 65: mn=65
\n" ); document.write( "Find m and n.\r
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\n" ); document.write( "\n" ); document.write( "The Differ equation gives n=m+8. Use this in the Product equation.
\n" ); document.write( "m(m+8)=65
\n" ); document.write( "m^2+8m-65=0, which we can factor, so let's do that:
\n" ); document.write( "(m+5)(m-13) ---- will that work? No. Gives -8m instead of +8m.
\n" ); document.write( "(m-5)(m+13) ---- Will that work? Yes. 13m-5m=8m, and product in const. term is -65.\r
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\n" ); document.write( "\n" ); document.write( "OKAY, solution to the quadratic formed is m=5 or m=-13.
\n" ); document.write( "What about n?
\n" ); document.write( "n-m=8
\n" ); document.write( "n=m+8
\n" ); document.write( "For m=5, n=13.
\n" ); document.write( "For m=-13, n=-5.\r
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\n" ); document.write( "\n" ); document.write( "ANSWER: Both solutions fit the description. Either the numbers are -5 and -13, or they are 5 and 13.
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