document.write( "Question 180789: x2 -6x-7=0 \n" ); document.write( "
Algebra.Com's Answer #135504 by jim_thompson5910(35256)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "\"x%5E2-6x-7=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "Notice we have a quadratic equation in the form of \"ax%5E2%2Bbx%2Bc\" where \"a=1\", \"b=-6\", and \"c=-7\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for x\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\" Start with the quadratic formula\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-%28-6%29+%2B-+sqrt%28+%28-6%29%5E2-4%281%29%28-7%29+%29%29%2F%282%281%29%29\" Plug in \"a=1\", \"b=-6\", and \"c=-7\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+%28-6%29%5E2-4%281%29%28-7%29+%29%29%2F%282%281%29%29\" Negate \"-6\" to get \"6\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+36-4%281%29%28-7%29+%29%29%2F%282%281%29%29\" Square \"-6\" to get \"36\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+36--28+%29%29%2F%282%281%29%29\" Multiply \"4%281%29%28-7%29\" to get \"-28\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+36%2B28+%29%29%2F%282%281%29%29\" Rewrite \"sqrt%2836--28%29\" as \"sqrt%2836%2B28%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+64+%29%29%2F%282%281%29%29\" Add \"36\" to \"28\" to get \"64\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+sqrt%28+64+%29%29%2F%282%29\" Multiply \"2\" and \"1\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B-+8%29%2F%282%29\" Take the square root of \"64\" to get \"8\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%286+%2B+8%29%2F%282%29\" or \"x+=+%286+-+8%29%2F%282%29\" Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%2814%29%2F%282%29\" or \"x+=++%28-2%29%2F%282%29\" Combine like terms. \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+7\" or \"x+=+-1\" Simplify. \r
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\n" ); document.write( "\n" ); document.write( "So the answers are \"x+=+7\" or \"x+=+-1\" \r
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