document.write( "Question 13893: hi, i an usually good with systems but this one is giving me trouble and i have a test tomorrow and could really use some help!
\n" ); document.write( "3x+2y=12
\n" ); document.write( "-4x+5z=12
\n" ); document.write( "y-4z=-13
\n" ); document.write( "thanx!!! \n" ); document.write( "

Algebra.Com's Answer #6996 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
1) $\"3x%2B2y=12\"$
\n" ); document.write( "2) $\"-4x%2B5z=12\"$
\n" ); document.write( "3) $\"y-4z=-13\"$ Solve this for y: $\"y+=+4z-13\"$ and substitute into equation 1)\r
\n" ); document.write( "\n" ); document.write( "1) $\"3x+%2B+2%284z-13%29+=+12\"$ Simplify.
\n" ); document.write( " $\"3x+%2B+8z+-+26+=+12\"$
\n" ); document.write( "1a) $\"3x+%2B+8z+=+38\"$ Now take equation 2)
\n" ); document.write( "2) $\"-4x+%2B+5z+=+12\"$ Multiply equ. 1a) by 4 and equ. 2) by 3.\r
\n" ); document.write( "\n" ); document.write( "1b) $\"12x+%2B+32z+=+152\"$
\n" ); document.write( "2a) $\"-12x+%2B+15z+=+36\"$ Now add these two to eliminate the x-term.\r
\n" ); document.write( "\n" ); document.write( " $\"47z+=+188\"$ Divide both sides by 47.
\n" ); document.write( " $\"z+=+4\"$ Substitute this into $\"y+=+4z+-+13\"$ and solve for y.
\n" ); document.write( " $\"y+=+4%284%29+-+13\"$
\n" ); document.write( " $\"y+=+3\"$ Substitute this into equation 1) and solve for x.\r
\n" ); document.write( "\n" ); document.write( " $\"3x+%2B+2%283%29+=+12\"$
\n" ); document.write( " $\"3x+=+6\"$
\n" ); document.write( " $\"x+=+2\"$ \r
\n" ); document.write( "\n" ); document.write( "x = 2
\n" ); document.write( "y = 3
\n" ); document.write( "z = 4\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

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