document.write( "Question 149605: Please help.
\n" ); document.write( "1. If x = 1 and x = -8, then form a quadratic equation. I have no idea where to even begin an equation.
\n" ); document.write( "2. 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. \r
\n" ); document.write( "\n" ); document.write( "Iknow if discriminant is less than zero no solutions are defined. But I don't know how to explain why or how to begin an example. Please explain and keep it as simplistic as possible so that I can understand. Like if you were explaining it to a 9 year old. \r
\n" ); document.write( "\n" ); document.write( "Thank you so much for all your time and help!!!!!
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Algebra.Com's Answer #109746 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
# 1\r
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\n" ); document.write( "\n" ); document.write( "Start with the given zeros\r
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\n" ); document.write( "\n" ); document.write( "\"x=1\" and \"x=-8\"\r
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\n" ); document.write( "\n" ); document.write( "Get all terms to the left side in each case (ie subtract 1 from both sides in the first equation and add 8 to both sides in the second equation)\r
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\n" ); document.write( "\n" ); document.write( "\"x-1=0\" and \"x%2B8=0\"\r
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\n" ); document.write( "\n" ); document.write( "Now use the zero product property in reverse to join the factors.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-1%29%28x%2B8%29=0\"\r
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\n" ); document.write( "\n" ); document.write( "FOIL and multiply\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B7x-8=0\"\r
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\n" ); document.write( "\n" ); document.write( "Answer:\r
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\n" ); document.write( "\n" ); document.write( "So the polynomial with zeros of \"x=1\" and \"x=-8\" is\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B7%2Ax-8\"\r
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\n" ); document.write( "\n" ); document.write( "Notice how if we graph \"y=x%5E2%2B7%2Ax-8\", we can see that the polynomial has roots of \"x=1\" and \"x=-8\"\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+x%5E2%2B7%2Ax-8+%29+\" Graph of \"y=x%5E2%2B7%2Ax-8\" with roots of \"x=1\" and \"x=-8\"\r
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\n" ); document.write( "\n" ); document.write( "# 2\r
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\n" ); document.write( "\n" ); document.write( "Remember the quadratic formula is \"x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "Where the discriminant is \"D=b%5E2-4ac\". So the quadratic formula could also look like \"x+=+%28-b+%2B-+sqrt%28+D+%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "If D<0, then we'll be taking the square root of a negative number (which we cannot do). So this results in 2 complex solutions (ie no 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 (or no real 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 (non real), this verifies our original claim.\r
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