document.write( "Question 149395: What type of solution do you get for quadratic equations where D<0? Give reasons for your answer. Also provide an example of such a quadratic equation and find the solution of the equation. \n" ); document.write( "
Algebra.Com's Answer #109606 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
If \"D%3C0\", then the quadratic will have two complex (ie non real) solutions. \r
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\n" ); document.write( "\n" ); document.write( "For example, let's find the discriminant for \"y=x%5E2%2B2x%2B5\"\r
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\n" ); document.write( "\n" ); document.write( "From \"x%5E2%2B2x%2B5\" we can see that \"a=1\", \"b=2\", and \"c=5\"\r
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\n" ); document.write( "\n" ); document.write( "\"D=b%5E2-4ac\" Start with the discriminant formula\r
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\n" ); document.write( "\n" ); document.write( "\"D=%282%29%5E2-4%281%29%285%29\" Plug in \"a=1\", \"b=2\", and \"c=5\"\r
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\n" ); document.write( "\n" ); document.write( "\"D=4-4%281%29%285%29\" Square \"2\" to get \"4\"\r
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\n" ); document.write( "\n" ); document.write( "\"D=4-20\" Multiply \"4%281%29%285%29\" to get \"%284%29%285%29=20\"\r
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\n" ); document.write( "\n" ); document.write( "\"D=-16\" Subtract \"20\" from \"4\" to get \"-16\"\r
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\n" ); document.write( "\n" ); document.write( "Since the discriminant is less than zero, this means that there are two complex solutions\r
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\n" ); document.write( "\n" ); document.write( "Now let's use the quadratic formula to find the solutions of \"y=x%5E2%2B2x%2B5\"\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-%282%29+%2B-+sqrt%28+%282%29%5E2-4%281%29%285%29+%29%29%2F%282%281%29%29\" Plug in \"a=1\", \"b=2\", and \"c=5\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B-+sqrt%28+4-4%281%29%285%29+%29%29%2F%282%281%29%29\" Square \"2\" to get \"4\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B-+sqrt%28+4-20+%29%29%2F%282%281%29%29\" Multiply \"4%281%29%285%29\" to get \"20\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B-+sqrt%28+-16+%29%29%2F%282%281%29%29\" Subtract \"20\" from \"4\" to get \"-16\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B-+sqrt%28+-16+%29%29%2F%282%29\" Multiply \"2\" and \"1\" to get \"2\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B-+4%2Ai%29%2F%282%29\" Take the square root of \"-16\" to get \"4%2Ai\". \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2+%2B+4%2Ai%29%2F%282%29\" or \"x+=+%28-2+-+4%2Ai%29%2F%282%29\" Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-2%29%2F%282%29+%2B+%284%2Ai%29%2F%282%29\" or \"x+=++%28-2%29%2F%282%29+-+%284%2Ai%29%2F%282%29\" Break up the fraction for each case. \r
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\n" ); document.write( "\n" ); document.write( "\"x+=+-1%2B2%2Ai\" or \"x+=++-1-2%2Ai\" Reduce. \r
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\n" ); document.write( "\n" ); document.write( "So our answers are \"x+=+-1%2B2%2Ai\" or \"x+=+-1-2%2Ai\" \r
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\n" ); document.write( "\n" ); document.write( "Since our answers are complex, this verifies our original claim.\r
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