document.write( "Question 1042996: prove, if x,y ∈ Q
\n" ); document.write( "then there are integers a,b,c
\n" ); document.write( "such that x=a/c and y=b/c
\n" ); document.write( "

Algebra.Com's Answer #658065 by LinnW(1048)\"\" \"About 
You can put this solution on YOUR website!
Since x and y are rational there exist
\n" ); document.write( "integers d and e such that \"x+=+d%2Fe\"
\n" ); document.write( "and integers f and g such that \"y+=+f%2Fg\"
\n" ); document.write( "Notice that
\n" ); document.write( "\"x+=+d%2Fe\" = \"x+=+%28d%2Fe%29%28g%2Fg%29\" = \"x+=+dg%2Feg\"
\n" ); document.write( "and
\n" ); document.write( "\"y+=+f%2Fg\" = \"y+=+%28f%2Fg%29%28e%2Fe%29\" = \"y+=+fe%2Feg\"
\n" ); document.write( "So we have \"x+=+dg%2Feg\" and \"y+=+fe%2Feg\"
\n" ); document.write( "Since the product of two integers is an integer,
\n" ); document.write( "we can set c = eg where c is an integer
\n" ); document.write( "set a = dg where a is an integer
\n" ); document.write( "set b = fe where b is an integer
\n" ); document.write( "Substituting we have
\n" ); document.write( "\"x+=+a%2Fc\" and \"y+=+b%2Fc\"
\n" ); document.write( "
\n" );