document.write( "Question 103983: could someone please help me find the x intercepts?
\n" ); document.write( "\"y%2Bx%5E2-7x-11\"
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Algebra.Com's Answer #75648 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
To find the x-intercepts, let y=0 and solve for x\r
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\n" ); document.write( "\n" ); document.write( "\"0=x%5E2-7x-11\"\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( "Starting with the general quadratic\r
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\n" ); document.write( "\n" ); document.write( "\"ax%5E2%2Bbx%2Bc=0\"\r
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\n" ); document.write( "\n" ); document.write( "the general solution using the quadratic equation is:\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29\"\r
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\n" ); document.write( "\n" ); document.write( "So lets solve \"x%5E2-7%2Ax-11=0\" ( notice \"a=1\", \"b=-7\", and \"c=-11\")\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%28--7+%2B-+sqrt%28+%28-7%29%5E2-4%2A1%2A-11+%29%29%2F%282%2A1%29\" Plug in a=1, b=-7, and c=-11\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%28+%28-7%29%5E2-4%2A1%2A-11+%29%29%2F%282%2A1%29\" Negate -7 to get 7\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%28+49-4%2A1%2A-11+%29%29%2F%282%2A1%29\" Square -7 to get 49 (note: remember when you square -7, you must square the negative as well. This is because \"%28-7%29%5E2=-7%2A-7=49\".)\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%28+49%2B44+%29%29%2F%282%2A1%29\" Multiply \"-4%2A-11%2A1\" to get \"44\"\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%28+93+%29%29%2F%282%2A1%29\" Combine like terms in the radicand (everything under the square root)\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%2893%29%29%2F%282%2A1%29\" Simplify the square root (note: If you need help with simplifying the square root, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B-+sqrt%2893%29%29%2F2\" Multiply 2 and 1 to get 2\r
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\n" ); document.write( "\n" ); document.write( "So now the expression breaks down into two parts\r
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\n" ); document.write( "\n" ); document.write( "\"x+=+%287+%2B+sqrt%2893%29%29%2F2\" or \"x+=+%287+-+sqrt%2893%29%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "Now break up the fraction\r
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\n" ); document.write( "\n" ); document.write( "\"x=%2B7%2F2%2Bsqrt%2893%29%2F2\" or \"x=%2B7%2F2-sqrt%2893%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "Simplify\r
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\n" ); document.write( "\n" ); document.write( "\"x=7+%2F+2%2Bsqrt%2893%29%2F2\" or \"x=7+%2F+2-sqrt%2893%29%2F2\"\r
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\n" ); document.write( "\n" ); document.write( "So these expressions approximate to\r
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\n" ); document.write( "\n" ); document.write( "\"x=8.32182538049648\" or \"x=-1.32182538049648\"\r
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\n" ); document.write( "\n" ); document.write( "So our solutions are:\r
\n" ); document.write( "\n" ); document.write( "\"x=8.32182538049648\" or \"x=-1.32182538049648\"\r
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\n" ); document.write( "\n" ); document.write( "Notice when we graph \"x%5E2-7%2Ax-11\", we get:\r
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\n" ); document.write( "\n" ); document.write( "when we use the root finder feature on a calculator, we find that \"x=8.32182538049648\" and \"x=-1.32182538049648\".So this verifies our answer
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