document.write( "Question 888322: Rosalyn is 7 years older than chris. In 5 years' time the product of their ages will be 588. find chris and rosalyn's ages now. \n" ); document.write( "
Algebra.Com's Answer #537295 by ankor@dixie-net.com(22740)\"\" \"About 
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let r = R's age
\n" ); document.write( "let c = C's age
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\n" ); document.write( "write an equation for each statement
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\n" ); document.write( "Rosalyn is 7 years older than chris.
\n" ); document.write( "r = c + 7
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\n" ); document.write( " In 5 years' time the product of their ages will be 588.
\n" ); document.write( "(r+5)(c+5) = 588
\n" ); document.write( "replace r with (c+7)
\n" ); document.write( "(c+7 + 5)(c+5) = 588
\n" ); document.write( "(c+12)(c+5) = 588
\n" ); document.write( "FOIL
\n" ); document.write( "c^2 + 5c + 12c + 60 - 588 = 0
\n" ); document.write( "c^2 + 17c - 528 = 0
\n" ); document.write( "You can us the quadratic formula, but this will factor to
\n" ); document.write( "(c+33)(c-16) = 0
\n" ); document.write( "the positive solution is all we want here
\n" ); document.write( "c = 16 yr is C's age
\n" ); document.write( "then
\n" ); document.write( "16 + 7 = 23 yrs is R's age
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\n" ); document.write( "See if that checks out, in five years time:
\n" ); document.write( "21 * 28 = 588\r
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