document.write( "Question 623550: danny is 7 years older than his brother. If the product of their ages is 120, find their ages. I have tried the equation n(n+7)=120. This does not make sense, however, since 7 does not divide into 120 evenly. \n" ); document.write( "
Algebra.Com's Answer #392155 by Theo(13342)\"\" \"About 
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danny is 15
\n" ); document.write( "his brother is 8
\n" ); document.write( "the difference in their ages is 15 - 8 = 7.
\n" ); document.write( "the product of their ages is 15 * 8 = 10 * 8 + 5 * 8 = 80 + 40 = 120
\n" ); document.write( "you had the right formula.
\n" ); document.write( "you just didn't know how to work it.
\n" ); document.write( "here's how:
\n" ); document.write( "let n equal danny's brother's age.
\n" ); document.write( "this make danny's age equal to n + 7.
\n" ); document.write( "this make the product of their ages equal n(n+7).
\n" ); document.write( "you are given that the product of their ages is 120, so:
\n" ); document.write( "n(n+7) = 120
\n" ); document.write( "simplify this expression to get:
\n" ); document.write( "n^2 + 7n = 120
\n" ); document.write( "subtract 120 from both sides of the equation to get:
\n" ); document.write( "n^2 + 7n - 120 = 0
\n" ); document.write( "factor to get:
\n" ); document.write( "(n+15)(n-8) = 0
\n" ); document.write( "solve for n to geet:
\n" ); document.write( "n = -15 or n = 8
\n" ); document.write( "-15 is no good because it's negative.
\n" ); document.write( "answer is that n = 8.
\n" ); document.write( "that's danny's brother's age.
\n" ); document.write( "danny is 7 more than that so danny is 15.
\n" ); document.write( "what you had was a quadratic equation that could be solved.
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