document.write( "Question 107970: Solve the system of equations using the addition (elimination) method.
\n" ); document.write( "If the answer is a unique solution, present it as an ordered pair: (x, y). If not, specify whether the answer is “no solution” or “infinitely many solutions.”
\n" ); document.write( "3x – 11y = 9
\n" ); document.write( "-9x + 33y = 18
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Algebra.Com's Answer #78683 by jim_thompson5910(35256)\"\" \"About 
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Solved by pluggable solver: Solving a System of Linear Equations by Elimination/Addition

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\n" ); document.write( " Lets start with the given system of linear equations
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\n" ); document.write( " \"3%2Ax-11%2Ay=9\"
\n" ); document.write( " \"-9%2Ax%2B33%2Ay=18\"
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\n" ); document.write( " In order to solve for one variable, we must eliminate the other variable. So if we wanted to solve for y, we would have to eliminate x (or vice versa).
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\n" ); document.write( " So lets eliminate x. In order to do that, we need to have both x coefficients that are equal but have opposite signs (for instance 2 and -2 are equal but have opposite signs). This way they will add to zero.
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\n" ); document.write( " So to make the x coefficients equal but opposite, we need to multiply both x coefficients by some number to get them to an equal number. So if we wanted to get 3 and -9 to some equal number, we could try to get them to the LCM.
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\n" ); document.write( " Since the LCM of 3 and -9 is -9, we need to multiply both sides of the top equation by -3 and multiply both sides of the bottom equation by -1 like this:
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\n" ); document.write( " \"-3%2A%283%2Ax-11%2Ay%29=%289%29%2A-3\" Multiply the top equation (both sides) by -3
\n" ); document.write( " \"-1%2A%28-9%2Ax%2B33%2Ay%29=%2818%29%2A-1\" Multiply the bottom equation (both sides) by -1
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\n" ); document.write( " So after multiplying we get this:
\n" ); document.write( " \"-9%2Ax%2B33%2Ay=-27\"
\n" ); document.write( " \"9%2Ax-33%2Ay=-18\"
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\n" ); document.write( " Notice how -9 and 9 and -27 and -33 add to zero (ie \"-9%2B9=0\" \"33%2B-33=0\")
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\n" ); document.write( " However -27 and -18 add to -45 (ie \"-27%2B-18=-45\");
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\n" ); document.write( " So we're left with
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\n" ); document.write( " \"0=-45\"
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\n" ); document.write( " which means no value of x or y value will satisfy the system of equations. So there are no solutions
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\n" ); document.write( " So this system is inconsistent
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