document.write( "Question 429957: I have to show my work and I only know how to do these on a calculator any help would be greatly appreciated!!\r
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Algebra.Com's Answer #298585 by ewatrrr(24785)\"\" \"About 
You can put this solution on YOUR website!

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document.write( "-5x - 4y + 12z = -140
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document.write( "9x - 8y + z = -649
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document.write( "3x - 2y + 6z = -290\r
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Solved by pluggable solver: Using Cramer's Rule to Solve Systems with 3 variables

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document.write( "  First let \"A=%28matrix%283%2C3%2C-5%2C-4%2C12%2C9%2C-8%2C1%2C3%2C-2%2C6%29%29\". This is the matrix formed by the coefficients of the given system of equations.
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document.write( "  Take note that the right hand values of the system are \"-140\", \"-649\", and \"-290\" and they are highlighted here: 
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document.write( "  These values are important as they will be used to replace the columns of the matrix A.
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document.write( "  Now let's calculate the the determinant of the matrix A to get \"abs%28A%29=506\". 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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document.write( "  Notation note: \"abs%28A%29\" denotes the determinant of the matrix A.
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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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document.write( "  Now compute the determinant of \"A%5Bx%5D\" to get \"abs%28A%5Bx%5D%29=-20240\". 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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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=%28-20240%29%2F%28506%29=-40\"
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document.write( "  So the first solution is \"x=-40\"
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document.write( "  We'll follow the same basic idea to find the other two solutions. Let's reset by letting \"A=%28matrix%283%2C3%2C-5%2C-4%2C12%2C9%2C-8%2C1%2C3%2C-2%2C6%29%29\" again (this is the coefficient matrix).
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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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document.write( "  Now compute the determinant of \"A%5By%5D\" to get \"abs%28A%5By%5D%29=17204\".
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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=%2817204%29%2F%28506%29=34\"
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document.write( "  So the second solution is \"y=34\"
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document.write( "  Let's reset again by letting \"A=%28matrix%283%2C3%2C-5%2C-4%2C12%2C9%2C-8%2C1%2C3%2C-2%2C6%29%29\" which is the coefficient matrix.
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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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document.write( "  Now compute the determinant of \"A%5Bz%5D\" to get \"abs%28A%5Bz%5D%29=-8602\".
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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=%28-8602%29%2F%28506%29=-17\"
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document.write( "  So the third solution is \"z=-17\"
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document.write( "  ====================================================================================
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document.write( "  Final Answer:
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document.write( "  So the three solutions are \"x=-40\", \"y=34\", and \"z=-17\" giving the ordered triple (-40, 34, -17)
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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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