document.write( "Question 147217: The ages of a man and his son are 40 and 12 respectively.Find:\r
\n" ); document.write( "\n" ); document.write( "> how many years ago was the man's age eight times the age of his son?
\n" ); document.write( "> how many years hence will the age of man be thrice the age of his son? \n" ); document.write( "
Algebra.Com's Answer #107585 by ptaylor(2198)\"\" \"About 
You can put this solution on YOUR website!
(1) Let x=number of years ago that the man's age was eight times his son's age
\n" ); document.write( "Our equation to solve is:\r
\n" ); document.write( "\n" ); document.write( "40-x=8(12-x) get rid of parens
\n" ); document.write( "40-x=96-8x subtract 40 from and add 8x to both sides
\n" ); document.write( "40-40-x+8x=96-40-8x+8x collect like terms\r
\n" ); document.write( "\n" ); document.write( "7x=56 divide each side by 7
\n" ); document.write( "x=8\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "40-8=8(12-8)
\n" ); document.write( "32=8*4
\n" ); document.write( "32=32\r
\n" ); document.write( "\n" ); document.write( "(2) Let y=the number of years hence that the man will be three times the age of his son
\n" ); document.write( "Our equation to solve:\r
\n" ); document.write( "\n" ); document.write( "40+y=3(12+y) get rid of parens\r
\n" ); document.write( "\n" ); document.write( "40+y=36+3y subtract 36 and also y from each side\r
\n" ); document.write( "\n" ); document.write( "40-36+y-y=36-36+3y-y collect like terms\r
\n" ); document.write( "\n" ); document.write( "4=2y divide each side by 2
\n" ); document.write( "y=2\r
\n" ); document.write( "\n" ); document.write( "CK
\n" ); document.write( "40+2=3(12+2)
\n" ); document.write( "42=3*14
\n" ); document.write( "42=42\r
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\n" ); document.write( "\n" ); document.write( "Hope this helps---ptaylor
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