document.write( "Question 142976: 1. Solve by completing the square. Find exact solutions. Then:
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Algebra.Com's Answer #104027 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"x%5E2-3x=18\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2-3x%2B9%2F4=18%2B9%2F4\" Take half of the x coefficient 3 to get \"3%2F2\". Now square \"3%2F2\" to get \"9%2F4\". Add this number to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2-3x%2B9%2F4=81%2F4\" Add 18 and \"9%2F4\" to get \"81%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-3%2F2%29%5E2=81%2F4\" Factor the left side. Now the left side is a complete square\r
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\n" ); document.write( "\n" ); document.write( "\"x-3%2F2=0%2B-sqrt%2881%2F4%29\" Take the square root of both sides\r
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\n" ); document.write( "\n" ); document.write( "\"x-3%2F2=9%2F2\" or \"x-3%2F2=-9%2F2\" Simplify and expand\r
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\n" ); document.write( "\n" ); document.write( "\"x=9%2F2%2B3%2F2\" or \"x=-9%2F2%2B3%2F2\" Add \"3%2F2\" to both sides in each case\r
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\n" ); document.write( "\n" ); document.write( "\"x=12%2F2\" or \"x=-6%2F2\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"x=6\" or \"x=-3\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "So the solutions are \"x=6\" or \"x=-3\"\r
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\n" ); document.write( "\n" ); document.write( "a)\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-3%2F2%29%5E2=81%2F4\" Start with the completed square\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-3%2F2%29%5E2-81%2F4=0\" Subtract \"81%2F4\" from both sides\r
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\n" ); document.write( "\n" ); document.write( "Now the equation is in vertex form \"a%28x-h%29%5E2%2Bk\" where the vertex is (h,k)\r
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\n" ); document.write( "\n" ); document.write( "So in this case, the vertex is \r
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\n" ); document.write( "\n" ); document.write( "The line of symmetry is simply the equation \"x=h\" where h is the x-coordinate of the vertex. So the axis of symmetry is \"x=3%2F2\" \r
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\n" ); document.write( "\n" ); document.write( "Remember, we're still using the general form \"a%28x-h%29%5E2%2Bk\", \r
\n" ); document.write( "\n" ); document.write( "Looking at \"%28x-3%2F2%29%5E2-81%2F4\", we can see that \"a=1\". Since \"a%3E0\", this means that the parabola opens up and there is a minimum. So the minimum occurs at the vertex which means that the minimum is \"-81%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "Finally here's a sketch to visually verify our answers\r
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\n" ); document.write( "\n" ); document.write( "\"graph%28500%2C500%2C-20%2C20%2C-22%2C22%2C%28x-3%2F2%29%5E2-81%2F4%29\"
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