document.write( "Question 148374: How would I go about solving a system of equations with three equations and three variables. \r
\n" ); document.write( "\n" ); document.write( "4x-4y-z=38
\n" ); document.write( "x+4y-3z=6
\n" ); document.write( "-3x+2y-z=-14\r
\n" ); document.write( "\n" ); document.write( "Please explain step by step, I would appreciate it. Thank you.
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Algebra.Com's Answer #108942 by Fombitz(32388)\"\" \"About 
You can put this solution on YOUR website!
There are several methods to choose from.
\n" ); document.write( "One of them is the substitution method.
\n" ); document.write( "1.\"4x-4y-z=38\"
\n" ); document.write( "2.\"x%2B4y-3z=6\"
\n" ); document.write( "3.\"-3x%2B2y-z=-14\"
\n" ); document.write( "You can use eq. 2 to come up with an expression for x in terms of y and z and substitute into eqs. 1 and 3.
\n" ); document.write( "2.\"x%2B4y-3z=6\"
\n" ); document.write( "\"x=-4y%2B3z%2B6\"
\n" ); document.write( "Now substitute into eq. 1,
\n" ); document.write( "1.\"4x-4y-z=38\"
\n" ); document.write( "1.\"4%28-4y%2B3z%2B6%29-4y-z=38\"
\n" ); document.write( "1.\"%28-16y%2B12z%2B24%29-4y-z=38\"
\n" ); document.write( "1.\"-20y%2B11z%2B24=38\"
\n" ); document.write( "1.\"-20y%2B11z=14\"
\n" ); document.write( "and eq. 3,
\n" ); document.write( "3.\"-3x%2B2y-z=-14\"
\n" ); document.write( "3.\"-3%28-4y%2B3z%2B6%29%2B2y-z=-14\"
\n" ); document.write( "3.\"%2812y-9z-18%29%2B2y-z=-14\"
\n" ); document.write( "3.\"14y-10z-18=-14\"
\n" ); document.write( "3.\"14y-10z=4\"
\n" ); document.write( "3.\"7y-5z=2\"
\n" ); document.write( "Now you've reduce from three variables to two variables.
\n" ); document.write( "1.\"-20y%2B11z=14\"
\n" ); document.write( "3.\"7y-5z=2\"
\n" ); document.write( "You can again do a substitution to get y in terms of z.
\n" ); document.write( "From new eq. 1,
\n" ); document.write( "1.\"-20y%2B11z=14\"
\n" ); document.write( "1.\"-20y=-11z%2B14\"
\n" ); document.write( "1.\"y=%2811z-14%29%2F20\"
\n" ); document.write( "Now substitute this value into new eq. 3.
\n" ); document.write( "3.\"7y-5z=2\"
\n" ); document.write( "3.\"%287%2811z-14%29%2F20%29-5z=2\"
\n" ); document.write( "3.\"%287%2811z-14%29%29-100z=40\"
\n" ); document.write( "3.\"%2877z-98%29-100z=40\"
\n" ); document.write( "3.\"-23z-98=40\"
\n" ); document.write( "3.\"-23z=138\"
\n" ); document.write( "\"z=-6\"
\n" ); document.write( "Now go backwards and substitute to find y and then x.
\n" ); document.write( "3.\"7y-5z=2\"
\n" ); document.write( "\"7y-5%28-6%29=2\"
\n" ); document.write( "\"7y%2B30=2\"
\n" ); document.write( "\"7y=-28\"
\n" ); document.write( "\"y=-4\"
\n" ); document.write( "And finally x,
\n" ); document.write( "\"x=-4y%2B3z%2B6\"
\n" ); document.write( "\"x=-4%28-4%29%2B3%28-6%29%2B6\"
\n" ); document.write( "\"x=16-18%2B6\"
\n" ); document.write( "\"x=4\"
\n" ); document.write( "Your solution is therefore,
\n" ); document.write( "(x,y,z,)=(4,-4,-6)
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