document.write( "Question 274516: How do you solve the equation: 0=3x-9√x-14? \n" ); document.write( "
Algebra.Com's Answer #200317 by Theo(13342)\"\" \"About 
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equation is:\r
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\n" ); document.write( "\n" ); document.write( "0=3x-9√x-14?\r
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\n" ); document.write( "\n" ); document.write( "let k = sqrt(x)\r
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\n" ); document.write( "\n" ); document.write( "equation becomes:\r
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\n" ); document.write( "\n" ); document.write( "0 = 3k^2 - 9k - 14\r
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\n" ); document.write( "\n" ); document.write( "this is a quadratic equation.\r
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\n" ); document.write( "\n" ); document.write( "factor using the quadratic formula of k = \"%28-b+%2B-+sqrt%28b%5E2-4ac%29%29%2F%282a%29\"\r
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\n" ); document.write( "\n" ); document.write( "a = 3
\n" ); document.write( "b = -9
\n" ); document.write( "c = -14
\n" ); document.write( "2a = 6
\n" ); document.write( "-b = 9
\n" ); document.write( "b^2 = 81
\n" ); document.write( "4ac = -168
\n" ); document.write( "b^2 - 4ac = 81 + 168 = 249\r
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\n" ); document.write( "\n" ); document.write( "quadratic formula becomes k = \"%289+%2B-+sqrt%28249%29%29%2F%286%29\" which becomes:\r
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\n" ); document.write( "\n" ); document.write( "k = (9 +/- 5.77973384)/6 which becomes:\r
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\n" ); document.write( "\n" ); document.write( "k = 4.12995564
\n" ); document.write( "k = -1.12995564\r
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\n" ); document.write( "\n" ); document.write( "confirm these are correct by plugging into the equation of 3k^2 - 9k - 14 = 0.\r
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\n" ); document.write( "\n" ); document.write( "once confirmed (done already), then you need to translate the k to x using the formula you used to derive k.\r
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\n" ); document.write( "\n" ); document.write( "that formula was \"k+=+sqrt%28x%29\"\r
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\n" ); document.write( "\n" ); document.write( "square both sides of this equation to get \"x+=+k%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "your answers of:\r
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\n" ); document.write( "\n" ); document.write( "k = 4.12995564
\n" ); document.write( "k = -1.12995564\r
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\n" ); document.write( "\n" ); document.write( "become:\r
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\n" ); document.write( "\n" ); document.write( "x = 17.05653359
\n" ); document.write( "x = 1.276799748\r
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\n" ); document.write( "\n" ); document.write( "plug these into the original equation of \"3x+-9%2Asqrt%28x%29+-+14+=+0\" to confirm they are good.\r
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\n" ); document.write( "\n" ); document.write( "the value of 17.05653359 is confirmed as good since \"sqrt%2817.05653359%29\" = +/- 4.12995564 except that you have to use the positive square root only.\r
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\n" ); document.write( "\n" ); document.write( "the value of 1.276799748 is confirmed as good since \"sqrt%281.276799748%29\" = +/- 1.12995564 except that you have to use the negative square root only.
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