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You can put this solution on YOUR website!
3x+4y+z=7
\n" ); document.write( "2y+z=3
\n" ); document.write( "-5+3y+8z=-31
\n" ); document.write( "(the 2y is suppose to be listed under the 4y) could anyone explain how this works??
\n" ); document.write( "--------------
\n" ); document.write( "I'll assume you meant -5x in the 3rd line.
\n" ); document.write( "There are several ways to do these. One is elimination and substitution as follows:
\n" ); document.write( "3x+ 4y + z = 7 (x 5) --> 15x + 20y + 5z = 35
\n" ); document.write( "0x+ 2y + z = 3
\n" ); document.write( "-5x+3y + 8z= -31 (x3)--> -15x+ 9y + 24z = -93
\n" ); document.write( "-------------
\n" ); document.write( "Since there's no x in the 2nd line, eliminate x in one of the other 2.
\n" ); document.write( " 15x + 20y + 5z = 35
\n" ); document.write( "-15x+ 9y + 24z = -93
\n" ); document.write( "--------------------- Add
\n" ); document.write( "0x + 29y + 29z = -58
\n" ); document.write( "y + z = -2
\n" ); document.write( "2y+ z = 3 2nd equation
\n" ); document.write( "--------- Subtract
\n" ); document.write( "-y = -5
\n" ); document.write( "y = 5
\n" ); document.write( "------ Then sub for y into y+z = -2
\n" ); document.write( "z = -7
\n" ); document.write( "-------- Sub for y and z into 3x+4y+z=7
\n" ); document.write( "x = -2
\n" ); document.write( "-----------
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\n" ); document.write( "Another method uses determinants.
\n" ); document.write( "3x+ 4y + z = 7
\n" ); document.write( "0x+ 2y + z = 3
\n" ); document.write( "-5x+3y + 8z= -31
\n" ); document.write( "|+x y z 1|
\n" ); document.write( "|+3 4 1 7|
\n" ); document.write( "|+0 2 1 3| = 0
\n" ); document.write( "|-5 2 1 3|
\n" ); document.write( "I made an Excel sheet that solves those, and there are sites online that do them up to 10x10, too.
\n" ); document.write( "If you're interested, email me via the thank you note.
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