document.write( "Question 187294: Solve the linear system with a single solution or using the addtion and substitution method. \r
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document.write( "14)2x-y+3z=14
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document.write( " x+y-2z=-5
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document.write( " 3x+y- z=2 \r
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document.write( "18) x-3y+2z=-11
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document.write( " 2x-4y+3z=-15
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document.write( " 3x-5y-4z=5''.
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Algebra.Com's Answer #140391 by Alan3354(69443)![]() ![]() You can put this solution on YOUR website! Solve each system in three variables \n" ); document.write( "14) \n" ); document.write( "2x-y+3z=14 \n" ); document.write( "x+y-2z=-5 \n" ); document.write( "3x+y- z=2 \n" ); document.write( "------------ \n" ); document.write( "Elimination and substitution is one way to do these. \n" ); document.write( "1st, pick a variable to eliminate from 2 of the eqns. Since y has a coeff of 1 in all 3, it's the easiest. \n" ); document.write( "Add eqn 3 to eqn 1, and then subtract it from eqn 2. \n" ); document.write( "2x-y+3z=14 \n" ); document.write( "3x+y- z=2 \n" ); document.write( "------------- \n" ); document.write( "5x+0y+2z = 16 Eqn A \n" ); document.write( "------------- \n" ); document.write( "x+y-2z=-5 \n" ); document.write( "3x+y- z=2 \n" ); document.write( "---------- \n" ); document.write( "-2x+0y-z = -7 Eqn B \n" ); document.write( "Now there are 2 eqns in x and z \n" ); document.write( "Multiply Eqn A and B by something to get the same coeff for either x or z. \n" ); document.write( "Multiply B by 2 to get 2z in both \n" ); document.write( "5x+0y+2z = 16 Eqn A \n" ); document.write( "-4x-2z = -14 Eqn B times 2 \n" ); document.write( "------------- Add these \n" ); document.write( "x = 2 \n" ); document.write( "----- \n" ); document.write( "Sub x into Eqn A, find z \n" ); document.write( "z = 3 \n" ); document.write( "--------- \n" ); document.write( "Sub z and z into any eqn to find y \n" ); document.write( "y = -2 \n" ); document.write( "------ \n" ); document.write( "x = 2 \n" ); document.write( "y = -1 \n" ); document.write( "z = 3 \n" ); document.write( "---------------- \n" ); document.write( "Try this one. email me via the thank you note for help, or to check you work. \n" ); document.write( "18) \n" ); document.write( "x-3y+2z=-11 \n" ); document.write( "2x-4y+3z=-15 \n" ); document.write( "3x-5y-4z=5 \n" ); document.write( " |