document.write( "Question 172174: If possible, solve the system of equations. Use any method. If there is not unique solution to the system, state the reason\r
\n" ); document.write( "\n" ); document.write( "2x-9y=9 (1)
\n" ); document.write( "-18x+81y= -81 (2)\r
\n" ); document.write( "\n" ); document.write( "What is the solution to this system?\r
\n" ); document.write( "\n" ); document.write( "Type an ordered pair. Type N if there is no solution. Type I if there is infinitely many solutions.\r
\n" ); document.write( "\n" ); document.write( "Which of the statements below is a good explanation for the solution?\r
\n" ); document.write( "\n" ); document.write( "The graphs intersect at one point, so the solution is unique.\r
\n" ); document.write( "\n" ); document.write( "The graphs of two equations represent the same line.\r
\n" ); document.write( "\n" ); document.write( "The graphs of the two equations never intersect.
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Algebra.Com's Answer #127220 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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\n" ); document.write( "\n" ); document.write( "Start with the given system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%282x-9y=9%2C-18x%2B81y=-81%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"9%282x-9y%29=9%289%29\" Multiply the both sides of the first equation by 9.\r
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\n" ); document.write( "\n" ); document.write( "\"18x-81y=81\" Distribute and multiply.\r
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\n" ); document.write( "\n" ); document.write( "So we have the new system of equations:\r
\n" ); document.write( "\n" ); document.write( "\"system%2818x-81y=81%2C-18x%2B81y=-81%29\"\r
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\n" ); document.write( "\n" ); document.write( "Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:\r
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\n" ); document.write( "\n" ); document.write( "\"%2818x-81y%29%2B%28-18x%2B81y%29=%2881%29%2B%28-81%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"%2818x%2B-18x%29%2B%28-81y%2B81y%29=81%2B-81\" Group like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"0x%2B0y=0\" Combine like terms. Notice how the x terms cancel out.\r
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\n" ); document.write( "\n" ); document.write( "\"0=0\"Simplify.\r
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\n" ); document.write( "\n" ); document.write( "Since \"0=0\" is ALWAYS true, this means that there are an infinite number of solutions. So the system is consistent and dependent.\r
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\n" ); document.write( "\n" ); document.write( "Graphically, these two equations are really the SAME equation. So this means that there are an infinite number of intersections.
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