document.write( "Question 130247: srry lost my other account password the ones next to each other are all one problem\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "x=y+1 x+2y=7\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "3x-y=2 y=2x-9\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #95127 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
# 1\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"x%2B2y=7\"
\n" ); document.write( "\"x=y%2B1\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%2B1%2B2y=7\" Plug in \"x=y%2B1\" into the first equation. In other words, replace each \"x\" with \"y%2B1\". Notice we've eliminated the \"x\" variables. So we now have a simple equation with one unknown.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3y%2B1=7\" Combine like terms on the left side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3y=7-1\"Subtract 1 from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3y=6\" Combine like terms on the right side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%286%29%2F%283%29\" Divide both sides by 3 to isolate y\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=2\" 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 \"y=2\", we can plug this into \"x=y%2B1\" to find \"x\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%282%29%2B1\" Substitute \"2\" for each \"y\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=3\" Simplify\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So our answer is \"x=3\" and \"y=2\" which also looks like \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Notice if we graph the two equations, we can see that their intersection is at . So this verifies our answer.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-5%2C+5%2C+-5%2C+5%2C+%287-x%29%2F%282%29%2C+x-1%29+\" Graph of \"x%2B2y=7\" (red) and \"x=y%2B1\" (green)\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "# 2\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Start with the given system\r
\n" ); document.write( "\n" ); document.write( "\"3x-y=2\"
\n" ); document.write( "\"y=2x-9\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3x-%282x-9%29=2\" Plug in \"y=2x-9\" into the first equation. In other words, replace each \"y\" with \"2x-9\". 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-2x%2B9=2\" Distribute the negative\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x%2B9=2\" Combine like terms on the left side\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=2-9\"Subtract 9 from both sides\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=-7\" Combine like terms on the right side\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=-7\", we can plug this into \"y=2x-9\" to find \"y\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=2%28-7%29-9\" Substitute \"-7\" for each \"x\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=-23\" Simplify\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-7\" and \"y=-23\" which also looks like \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );