document.write( "Question 105788: I need help with this problem. I have tried everthing.
\n" ); document.write( "x+2y-z=-4
\n" ); document.write( "3x+y-2z=-9
\n" ); document.write( "2x-z=-5 \n" ); document.write( "

Algebra.Com's Answer #76978 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
1. $\"x%2B2y-z=-4\"$
\n" ); document.write( "2. $\"3x%2By-2z=-9\"$
\n" ); document.write( "3. $\"2x-z=-5\"$
\n" ); document.write( "Let's use equation 3 to solve for z in terms of x.
\n" ); document.write( "3. $\"2x-z=-5\"$
\n" ); document.write( "3. $\"-z=-5-2x\"$
\n" ); document.write( "3. $\"highlight%28z=5%2B2x%29\"$
\n" ); document.write( "Substitute into equations 1 and 2.
\n" ); document.write( "1. $\"x%2B2y-z=-4\"$
\n" ); document.write( "1. $\"x%2B2y-%285%2B2x%29=-4\"$
\n" ); document.write( "1. $\"x%2B2y-5-2x=-4\"$
\n" ); document.write( "1. $\"highlight%28-3x%2B2y=1%29\"$
\n" ); document.write( "2. $\"3x%2By-2z=-9\"$
\n" ); document.write( "2. $\"3x%2By-2%285%2B2x%29=-9\"$
\n" ); document.write( "2. $\"3x%2By-10-4x%29=-9\"$
\n" ); document.write( "2. $\"highlight%28-x%2By=1%29\"$
\n" ); document.write( "Now use equation 2 to solve for y.
\n" ); document.write( "2. $\"-x%2By=1\"$
\n" ); document.write( "2. $\"y=1%2Bx\"$
\n" ); document.write( "Substitute into equation 1.
\n" ); document.write( "1. $\"-3x%2B2y=1\"$
\n" ); document.write( "1. $\"-3x%2B2%281%2Bx%29=1\"$
\n" ); document.write( "1. $\"-3x%2B2%2B2x%29=1\"$
\n" ); document.write( "1. $\"-x=-1\"$
\n" ); document.write( "1. $\"x=1\"$
\n" ); document.write( "Back substitute into 2.
\n" ); document.write( "2. $\"y=1%2Bx\"$
\n" ); document.write( "2. $\"y=1%2B1\"$
\n" ); document.write( " $\"y=2\"$
\n" ); document.write( "Back substitute into 3.
\n" ); document.write( "3. $\"z=5%2B2x\"$
\n" ); document.write( "3. $\"z=5%2B2%281%29\"$
\n" ); document.write( " $\"z=7\"$
\n" ); document.write( "Check your answers.
\n" ); document.write( "1. $\"x%2B2y-z=-4\"$
\n" ); document.write( "1. $\"1%2B2%281%29-7=-4\"$
\n" ); document.write( "1. $\"3-7=-4\"$
\n" ); document.write( "1. $\"-4=-4\"$
\n" ); document.write( "Good answer.
\n" ); document.write( "2. $\"3x%2By-2z=-9\"$
\n" ); document.write( "2. $\"3%281%29%2B1-2%287%29=-9\"$
\n" ); document.write( "2. $\"3%2B1-14=-9\"$
\n" ); document.write( "2. $\"-9=-9\"$
\n" ); document.write( "Good answer.
\n" ); document.write( "3. $\"2x-z=-5\"$
\n" ); document.write( "3. $\"2%281%29-7=-5\"$
\n" ); document.write( "3. $\"-5=-5\"$
\n" ); document.write( "Good answer.
\n" ); document.write( "x=1, y=1, z=7 \n" ); document.write( "

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