document.write( "Question 208208: SYSTEM OF 3 EQUATIONS WITH 3 UNKNOWNS\r
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\n" ); document.write( "\n" ); document.write( "FIND THE SOLUTION SET FOR THE FOLLOWING SYSTEM OF EQUATIONS:\r
\n" ); document.write( "\n" ); document.write( " 4X -2Y -3Z = 8
\n" ); document.write( " 5X +3Y -4Z = 4
\n" ); document.write( " 6X -4Y -5Z = 12
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Algebra.Com's Answer #157517 by pjalgeb(9)\"\" \"About 
You can put this solution on YOUR website!
REQUIRED: Find the solution set {(x, y z)} for the system given.\r
\n" ); document.write( "\n" ); document.write( "SOLUTION:\r
\n" ); document.write( "\n" ); document.write( "The augmented 3x3 matrix for the above system of equations is:\r
\n" ); document.write( "\n" ); document.write( " | 4 -2 -3 | 8 |
\n" ); document.write( " | 5 3 -4 | 4 |
\n" ); document.write( " | 6 -4 -5 | 12 |\r
\n" ); document.write( "\n" ); document.write( "By Cramers Rule: \r
\n" ); document.write( "\n" ); document.write( "\"x+=+Dx%2FD\"
\n" ); document.write( "\"y+=+Dy%2FD\"
\n" ); document.write( "\"z+=+Dz%2FD\"\r
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\n" ); document.write( "\n" ); document.write( "First, lets solve for D, Dx, Dy and Dz:\r
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\n" ); document.write( "\n" ); document.write( "D = | 4 -2 -3 |
\n" ); document.write( " | 5 3 -4 |
\n" ); document.write( " | 6 -4 -5 | \r
\n" ); document.write( "\n" ); document.write( "D = 4(-15-16) -5(10-12) +6(8+9)
\n" ); document.write( "D = 4(-31) -5(-2)+ 6(17)
\n" ); document.write( "D = -124 +10 +102
\n" ); document.write( "D = -124 -112\r
\n" ); document.write( "\n" ); document.write( "\"D+=+-12\"\r
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\n" ); document.write( "\n" ); document.write( "Dx = | 8 -2 -3 |
\n" ); document.write( " | 4 3 -4 |
\n" ); document.write( " | 12 -4 -5 |\r
\n" ); document.write( "\n" ); document.write( "Dx = 8(-15-16) -4(10-12) + 12(8+9)
\n" ); document.write( "Dx = 8(-31) -4(-2) + 12(17)
\n" ); document.write( "Dx = -248 +8 + 204
\n" ); document.write( "Dx = -248 +212\r
\n" ); document.write( "\n" ); document.write( "\"Dx+=+-36\"\r
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\n" ); document.write( "\n" ); document.write( "Dy = | 4 8 -3 |
\n" ); document.write( " | 5 4 -4 |
\n" ); document.write( " | 6 12 -5 | \r
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\n" ); document.write( "\n" ); document.write( "Dy = 4(-20+48) -5(-40+36) +6(-32+12)
\n" ); document.write( "Dy = 4(28) -5(-4) +6(-20)
\n" ); document.write( "Dy = 112 +20 -120
\n" ); document.write( "Dy = 132 -120\r
\n" ); document.write( "\n" ); document.write( "\"Dy+=+12\"\r
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\n" ); document.write( "\n" ); document.write( "Dz = | 4 -2 8 |
\n" ); document.write( " | 5 3 4 |
\n" ); document.write( " | 6 -4 12 |\r
\n" ); document.write( "\n" ); document.write( "Dz = 4(36+16) -5(-24+32) +6(-8-24)
\n" ); document.write( "Dz = 4(52) -5(8) +6(-32)
\n" ); document.write( "Dz = 208 -40 -192
\n" ); document.write( "Dz = 168 -192\r
\n" ); document.write( "\n" ); document.write( "\"Dz+=+-24\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+Dx%2FD+=+-36%2F-12\"
\n" ); document.write( "\"x+=+3\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=+Dy%2FD+=+12%2F-12\"
\n" ); document.write( "\"y+=+-1\"\r
\n" ); document.write( "\n" ); document.write( "\"z+=+Dz%2FD+=+-24%2F-12\"
\n" ); document.write( "\"z+=+2\"\r
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\n" ); document.write( "\n" ); document.write( "Answer: The solution set is {(3,-1,2)}
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