document.write( "Question 576079: Please help solve the following. The instructions read \"Solve each system by triangularizing the augmented matrix and using back-substitution. If the system is linearly dependent, give the solution in terms of a parameter. If the system has coincident dependence, answer in set notation.
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document.write( "x + 3y +5z = 20
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document.write( "2x + 3y +4z = 16
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document.write( "x + 2y +3z = 12
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document.write( "I listed the matrix as
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document.write( "1 3 5 20
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document.write( "2 2 4 16
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document.write( "1 2 3 12
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document.write( "I used the row operation -2R1 + R2 > R2 to get the matrix to
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document.write( "1 3 5 20
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document.write( "0 -3 -6 -24
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document.write( "1 2 3 12
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document.write( "I then used row operation -1R1 + R3 > R3 to get the matrix to
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document.write( "1 3 5 20
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document.write( "0 -3 -6 -24
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document.write( "0 -1 -2 -8
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document.write( "I then used -1/3R2 + R3 > R3 to get the matrix to
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document.write( "1 3 5 20
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document.write( "0 -3 -6 -24
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document.write( "0 0 0 0
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document.write( "I know the system is linearly dependent but do understand how to solve from here. Please provide detail. Thank you. (also please let me know if I have made a mistake so far. I was given the answer of (p-4, -2P+8, p) but do not know how to come up with the answer with what I have so far. \n" );
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Algebra.Com's Answer #369716 by jim_thompson5910(35256)![]() ![]() ![]() You can put this solution on YOUR website! You're doing great. I'm going to finish up.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Row 2 has the values 0 -3 -6 -24, which means that -3y -6z = -24. Solve for y to get\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-3y -6z = -24\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-3y = 6z -24\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = (6z)/(-3) -24/(-3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = -2z + 8\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now if you let z = P (ie let z be the free variable), then y = -2P + 8. So that explains why the second coordinate is -2P+8 and the third is P\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now that you know that z = P and y = -2P+8, you can use this to find x in terms of the free variable P (or z). So use the first equation (you can use any equation that has x in it)\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + 3y +5z = 20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x + 3(-2P+8) +5P = 20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x -6P+24 +5P = 20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x -P+24 = 20\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x -P = 20-24\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x -P = -4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = P-4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So the solutions are\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = P-4, y = -2P+8, and z = P\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "which form the ordered triple\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(P-4, -2P+8, P) \n" ); document.write( " |