document.write( "Question 164189: solve the system:
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document.write( "5x-3y+z=-7
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document.write( "4x+5y+3z=-2
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document.write( "2x-3y+5z=22
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document.write( "show work and i think you can solve it in the calculator by matrices right?
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document.write( "if you know both ways please show thanks!
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Algebra.Com's Answer #121996 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! solve the system: \n" ); document.write( "5x-3y+z=-7 \n" ); document.write( "4x+5y+3z=-2 \n" ); document.write( "2x-3y+5z=22 \n" ); document.write( "show work and i think you can solve it in the calculator by matrices right? \n" ); document.write( "if you know both ways please show thanks! \n" ); document.write( "------------------- \n" ); document.write( "You can do it by elimination and substitution, but that's tedious and error prone. \n" ); document.write( "If you calculator has the functionality, you can do a matrix solution on it. \n" ); document.write( "I have an Excel sheet that does it using determinants. \n" ); document.write( "By Excel: \n" ); document.write( "x = -3 \n" ); document.write( "y = -1 \n" ); document.write( "z = +5 \n" ); document.write( "----------- \n" ); document.write( "Using elimination and substitution: \n" ); document.write( "5x-3y+z=-7 eqn 1 \n" ); document.write( "4x+5y+3z=-2 eqn 2 \n" ); document.write( "2x-3y+5z=22 eqn 3 \n" ); document.write( "------------ \n" ); document.write( "Eqn 1 has a z coeff of 1, so muliply it by 3, and then by 5. \n" ); document.write( "5x-3y+z=-7 \n" ); document.write( "15x - 9y + 3z = -21 eqn 1 times 3 \n" ); document.write( " 4x + 5y + 3z = -2 eqn 2 \n" ); document.write( "11x - 14y = -19 Subtract eqn 2 \n" ); document.write( "---------------- \n" ); document.write( "5x-3y+z=-7 eqn 1 again \n" ); document.write( "25x - 15y + 5z = -35 eqn 1 times 5 \n" ); document.write( " 2x - 3y + 5z = 22 eqn 3 \n" ); document.write( "23x - 12y = -57 Subract eqn 3 \n" ); document.write( "------------- \n" ); document.write( "Now there are 2 eqns in 2 unknowns (x and y) \n" ); document.write( "11x - 14y = -19 \n" ); document.write( "23x - 12y = -57 \n" ); document.write( "Multiply the 1st times 6, and the 2nd times 7 to get the same coeff for y. \n" ); document.write( "66x - 84y = -114 \n" ); document.write( "161x -84y = -399 Subtract \n" ); document.write( "-95x = 285 \n" ); document.write( "x = -3 \n" ); document.write( "------------ \n" ); document.write( "Sub into 11x - 14y = -19 to get \n" ); document.write( "y = -1 \n" ); document.write( "----------- \n" ); document.write( "Sub x and y into any of the original 3 eqns to get \n" ); document.write( "z = +5\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |