document.write( "Question 772462: Two years ago, my age was four times that of my son. Eight years ago, my age was ten times that of my son. Find the age of my son now. \n" ); document.write( "

Algebra.Com's Answer #470905 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let $\"+f+\"$ = my age now
\n" ); document.write( "Let $\"+s+\"$ = my son's age now
\n" ); document.write( " $\"+f+-+2+\"$ = my age 2 yrs ago
\n" ); document.write( " $\"+s+-+2+\"$ = my son's age 2 yrs ago
\n" ); document.write( " $\"+f+-+8+\"$ = my age 8 yrs ago
\n" ); document.write( " $\"+s+-+8+\"$ = my son's age 8 yrs ago
\n" ); document.write( "------------------------------
\n" ); document.write( "(1) $\"+f-2+=+4%2A%28+s-2+%29+\"$
\n" ); document.write( "(2) $\"+f-8+=+10%2A%28+s-8+%29+\"$
\n" ); document.write( "---------------------
\n" ); document.write( "(1) $\"+f+-+2+=+4s+-+8+\"$
\n" ); document.write( "(1) $\"+f+-+4s+=+-6+\"$
\n" ); document.write( "and
\n" ); document.write( "(2) $\"+f+-+8+=+10s+-+80+\"$
\n" ); document.write( "(2) $\"+f+-+10s+=+-72+\"$
\n" ); document.write( "-------------------
\n" ); document.write( "Subtract (2) from (1)
\n" ); document.write( "(1) $\"+f+-+4s+=+-6+\"$
\n" ); document.write( "(2) $\"+-f+%2B+10s+=+72+\"$
\n" ); document.write( " $\"+6s+=+66+\"$
\n" ); document.write( " $\"+s+=+11+\"$
\n" ); document.write( "Plug this result back into either equation
\n" ); document.write( "(1) $\"+f-2+=+4%2A%28+11-2+%29+\"$
\n" ); document.write( "(1) $\"+f+-+2+=+36+\"$
\n" ); document.write( "(1) $\"+f+=+38+\"$
\n" ); document.write( "My son is 11 now
\n" ); document.write( "check:
\n" ); document.write( "(2) $\"+38-8+=+10%2A%28+11-8+%29+\"$
\n" ); document.write( "(2) $\"+30+=+10%2A3+\"$
\n" ); document.write( "(2) $\"+30+=+30+\"$
\n" ); document.write( "OK
\n" ); document.write( " \n" ); document.write( "

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