document.write( "Question 132477This question is from textbook Algebra 1
\n" ); document.write( ": y=x+5 and -3x+3y=15 \n" ); document.write( "
Algebra.Com's Answer #96829 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"-3x%2B3y=15\"
\n" ); document.write( "\"y=x%2B5\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-3x%2B3%28x%2B5%29=15\" Plug in \"y=x%2B5\" into the first equation. In other words, replace each \"y\" with \"x%2B5\". 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( "\"-3x%2B3x%2B15=15\" Distribute\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"15=15\" Combine like terms on the left side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"0=15-15\"Subtract 15 from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"0=0\" Combine like terms on the right side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since this equation is always true for any x value, this means x can equal any number. So there are an infinite number of solutions.
\n" ); document.write( "
\n" ); document.write( "
\n" );