document.write( "Question 252724: how do i use cramer's rule for three equations on this problem
\n" ); document.write( "5x-6y=7+7z
\n" ); document.write( "6x-4y+10z=-34
\n" ); document.write( "2x+4y=29+3z
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Algebra.Com's Answer #184789 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
The first goal is to get all of the variable terms to the left side for each equation.\r
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\n" ); document.write( "\n" ); document.write( "\"5x-6y=7%2B7z\" Start with the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"5x-6y-7z=7\" Subtract 7z from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%2B4y=29%2B3z\" Move onto the third equation.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%2B4y-3z=29\" Subtract 3z from both sides.\r
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\n" ); document.write( "\n" ); document.write( "So we now have the system\r
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\n" ); document.write( "\n" ); document.write( "\"system%285x-6y-7z=7%2C6x-4y%2B10z=-34%2C2x%2B4y-3z=29%29\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's use Cramer's Rule to solve this system\r
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Solved by pluggable solver: Using Cramer's Rule to Solve Systems with 3 variables

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\n" ); document.write( " First let \"A=%28matrix%283%2C3%2C5%2C-6%2C-7%2C6%2C-4%2C10%2C2%2C4%2C-3%29%29\". This is the matrix formed by the coefficients of the given system of equations.
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\n" ); document.write( " Take note that the right hand values of the system are \"7\", \"-34\", and \"29\" and they are highlighted here:
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\n" ); document.write( " These values are important as they will be used to replace the columns of the matrix A.
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\n" ); document.write( " Now let's calculate the the determinant of the matrix A to get \"abs%28A%29=-592\". To save space, I'm not showing the calculations for the determinant. However, if you need help with calculating the determinant of the matrix A, check out this solver.
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\n" ); document.write( " Notation note: \"abs%28A%29\" denotes the determinant of the matrix A.
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\n" ); document.write( " Now replace the first column of A (that corresponds to the variable 'x') with the values that form the right hand side of the system of equations. We will denote this new matrix \"A%5Bx%5D\" (since we're replacing the 'x' column so to speak).
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\n" ); document.write( " Now compute the determinant of \"A%5Bx%5D\" to get \"abs%28A%5Bx%5D%29=-1184\". Again, as a space saver, I didn't include the calculations of the determinant. Check out this solver to see how to find this determinant.
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\n" ); document.write( " To find the first solution, simply divide the determinant of \"A%5Bx%5D\" by the determinant of \"A\" to get: \"x=%28abs%28A%5Bx%5D%29%29%2F%28abs%28A%29%29=%28-1184%29%2F%28-592%29=2\"
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\n" ); document.write( " So the first solution is \"x=2\"
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\n" ); document.write( " We'll follow the same basic idea to find the other two solutions. Let's reset by letting \"A=%28matrix%283%2C3%2C5%2C-6%2C-7%2C6%2C-4%2C10%2C2%2C4%2C-3%29%29\" again (this is the coefficient matrix).
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\n" ); document.write( " Now replace the second column of A (that corresponds to the variable 'y') with the values that form the right hand side of the system of equations. We will denote this new matrix \"A%5By%5D\" (since we're replacing the 'y' column in a way).
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\n" ); document.write( " Now compute the determinant of \"A%5By%5D\" to get \"abs%28A%5By%5D%29=-2368\".
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\n" ); document.write( " To find the second solution, divide the determinant of \"A%5By%5D\" by the determinant of \"A\" to get: \"y=%28abs%28A%5By%5D%29%29%2F%28abs%28A%29%29=%28-2368%29%2F%28-592%29=4\"
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\n" ); document.write( " So the second solution is \"y=4\"
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\n" ); document.write( " Let's reset again by letting \"A=%28matrix%283%2C3%2C5%2C-6%2C-7%2C6%2C-4%2C10%2C2%2C4%2C-3%29%29\" which is the coefficient matrix.
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\n" ); document.write( " Replace the third column of A (that corresponds to the variable 'z') with the values that form the right hand side of the system of equations. We will denote this new matrix \"A%5Bz%5D\"
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\n" ); document.write( " Now compute the determinant of \"A%5Bz%5D\" to get \"abs%28A%5Bz%5D%29=1776\".
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\n" ); document.write( " To find the third solution, divide the determinant of \"A%5Bz%5D\" by the determinant of \"A\" to get: \"z=%28abs%28A%5Bz%5D%29%29%2F%28abs%28A%29%29=%281776%29%2F%28-592%29=-3\"
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\n" ); document.write( " So the third solution is \"z=-3\"
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\n" ); document.write( " Final Answer:
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\n" ); document.write( " So the three solutions are \"x=2\", \"y=4\", and \"z=-3\" giving the ordered triple (2, 4, -3)
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\n" ); document.write( " Note: there is a lot of work that is hidden in finding the determinants. Take a look at this 3x3 Determinant Solver to see how to get each determinant.
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\n" ); document.write( "\n" ); document.write( "If you need more help or practice with Cramer's Rule, check out this solver.
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