document.write( "Question 147702This question is from textbook
\n" ); document.write( ": hi, i need exact step by ste solution using elimination method and check.\r
\n" ); document.write( "\n" ); document.write( "15x+3y=-12
\n" ); document.write( " 2x+y=8
\n" ); document.write( "

Algebra.Com's Answer #108061 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Start with the given system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%2815x%2B3y=-12%2C2x%2By=8%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-3%282x%2By%29=-3%288%29\" Multiply the both sides of the second equation by -3.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-6x-3y=-24\" Distribute and multiply.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So we have the new system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%2815x%2B3y=-12%2C-6x-3y=-24%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"%2815x%2B3y%29%2B%28-6x-3y%29=%28-12%29%2B%28-24%29\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"%2815x%2B-6x%29%2B%283y%2B-3y%29=-12%2B-24\" Group like terms.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"9x%2B0y=-36\" Combine like terms. Notice how the y terms cancel out.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"9x=-36\" Simplify.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=%28-36%29%2F%289%29\" Divide both sides by \"9\" to isolate \"x\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x=-4\" Reduce.\r
\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( "\"15x%2B3y=-12\" Now go back to the first equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"15%28-4%29%2B3y=-12\" Plug in \"x=-4\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-60%2B3y=-12\" Multiply.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3y=-12%2B60\" Add \"60\" to both sides.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"3y=48\" Combine like terms on the right side.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y=%2848%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( "\"y=16\" Reduce.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So our answer is \"x=-4\" and \"y=16\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Which form the ordered pair .\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "This means that the system is consistent and independent.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Notice when we graph the equations, we see that they intersect at . So this visually verifies our answer.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " Graph of \"15x%2B3y=-12\" (red) and \"2x%2By=8\" (green) \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "---------------------------\r
\n" ); document.write( "\n" ); document.write( "Check:\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"15x%2B3y=-12\" Start with the first equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"15%2A%28-4%29%2B3%2A%2816%29=-12\" Plug in \"x=-4\" and \"y=16\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"-12=-12\" Evaluate and simplify the left side.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the equation is true, this means that (-4,16) is a solution of the first equation\r
\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( "\"2x%2By=8\" Start with the second equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2%2A%28-4%29%2B%2816%29=8\" Plug in \"x=-4\" and \"y=16\".\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"8=8\" Evaluate and simplify the left side.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since the equation is true, this means that (-4,16) is a solution of the second equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Since all of the equations of the system are true, this means that (-4,16) is a solution to the system. So this verifies our answer.
\n" ); document.write( "
\n" );