\r\n" );
document.write( "Substitution isn't the easiest way. Elimination is easier,\r\n" );
document.write( "But you specified substitution, so here goes:\r\n" );
document.write( "\r\n" );
document.write( "(1)
\r\n" );
document.write( "(2)
\r\n" );
document.write( "(3)
\r\n" );
document.write( "\r\n" );
document.write( "Pick any equation and solve for any letter:\r\n" );
document.write( "\r\n" );
document.write( "I'll arbitrarily pick equation 2 and arbitrarily solve for y\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "(4)
\r\n" );
document.write( "\r\n" );
document.write( "Substitute for y in (1)\r\n" );
document.write( "\r\n" );
document.write( "(1)
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "Multiply through by 4 to clear the fraction:\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "(5)
\r\n" );
document.write( "\r\n" );
document.write( "We notice that (3) contains the same letters as (5)\r\n" );
document.write( "\r\n" );
document.write( "Solve (3) for one of its letters.\r\n" );
document.write( "\r\n" );
document.write( "I'll arbitrarily solve (3) for z\r\n" );
document.write( "\r\n" );
document.write( "(3)
\r\n" );
document.write( "
\r\n" );
document.write( "(6)
\r\n" );
document.write( "\r\n" );
document.write( "Substitute in (5)\r\n" );
document.write( "\r\n" );
document.write( "(5)
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "Multiply by 2 to clear the fraction:\r\n" );
document.write( "\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "Substitute in (6)\r\n" );
document.write( "\r\n" );
document.write( "(6)
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "(4)
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "
\r\n" );
document.write( "\r\n" );
document.write( "(x,y,z) = (2,-3,4)\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" );
document.write( "