document.write( "Question 1093432: Solve the system using the substitution method. Show work
\n" ); document.write( "X-4y=-65, y=-3x \n" ); document.write( "

Algebra.Com's Answer #708067 by ikleyn(52781) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "

\r\n" );
document.write( "You are lucky !\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Because in the second equation the unknown \"y\" is just expressed via \"x\".\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "So, all you need to do is to replace \"y\" in the first equation by (-3x).\r\n" );
document.write( "\r\n" );
document.write( "Then you get the single equation for one unknown y:\r\n" );
document.write( "\r\n" );
document.write( "x - 4*(-3x) = -65,\r\n" );
document.write( "\r\n" );
document.write( "x + 12x = - 65  ====>  13x = -65  ====>  x =  = -5.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Last step is to find y.  For it, substitute x= -5 into your second original equation to get y = -3*(-5) = 15.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Answer.  x = -5,  y = 15.\r\n" );
document.write( "

\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );