document.write( "Question 114177: Solve the system by substitution.
\n" ); document.write( " 5x + 5y = 0
\n" ); document.write( " y = –3x – 2
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #83107 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"5x%2B5y=0\"
\n" ); document.write( "\"y=-3x-2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"5x%2B5%28-3x-2%29=0\" Plug in \"y=-3x-2\" into the first equation. In other words, replace each \"y\" with \"-3x-2\". Notice we've eliminated the \"y\" variables. So we now have a simple equation with one unknown.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"5x%2B-15x-10=0\" Distribute\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-10x-10=0\" Combine like terms on the left side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-10x=0%2B10\"Add 10 to both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-10x=10\" Combine like terms on the right side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%2810%29%2F%28-10%29\" Divide both sides by -10 to isolate x\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=-1\" Divide\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now that we know that \"x=-1\", we can plug this into \"y=-3x-2\" to find \"y\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=-3%28-1%29-2\" Substitute \"-1\" for each \"x\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=1\" Simplify\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-1\" and \"y=1\"
\n" ); document.write( "
\n" );