document.write( "Question 200162: Hi!\r
\n" ); document.write( "\n" ); document.write( "Use the substitution method to find all solutions of the system of equations. (Round each answer to two decimal places.)\r
\n" ); document.write( "\n" ); document.write( "{2x^2+4y=11
\n" ); document.write( " x^2-y^2=1/2\r
\n" ); document.write( "\n" ); document.write( "thanks for the homework help!
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Algebra.Com's Answer #150459 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"x%5E2-y%5E2=1%2F2\" Start with the second equation.\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2=1%2F2%2By%5E2\" Add \"y%5E2\" to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%5E2%2B4y=11\" Move back to the first equation.\r
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\n" ); document.write( "\n" ); document.write( "\"2%281%2F2%2By%5E2%29%2B4y=11\" Plug in \"x%5E2=1%2F2%2By%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "\"2%2B2y%5E2%2B4y=11\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"2%2B2y%5E2%2B4y-11=0\" Subtract 11 from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2y%5E2%2B4y-9=0\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "Notice that the quadratic \"2y%5E2%2B4y-9\" is in the form of \"Ay%5E2%2BBy%2BC\" where \"A=2\", \"B=4\", and \"C=-9\"\r
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\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for \"y\":\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%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( "\"y+=+%28-%284%29+%2B-+sqrt%28+%284%29%5E2-4%282%29%28-9%29+%29%29%2F%282%282%29%29\" Plug in \"A=2\", \"B=4\", and \"C=-9\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+sqrt%28+16-4%282%29%28-9%29+%29%29%2F%282%282%29%29\" Square \"4\" to get \"16\". \r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+sqrt%28+16--72+%29%29%2F%282%282%29%29\" Multiply \"4%282%29%28-9%29\" to get \"-72\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+sqrt%28+16%2B72+%29%29%2F%282%282%29%29\" Rewrite \"sqrt%2816--72%29\" as \"sqrt%2816%2B72%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+sqrt%28+88+%29%29%2F%282%282%29%29\" Add \"16\" to \"72\" to get \"88\"\r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+sqrt%28+88+%29%29%2F%284%29\" Multiply \"2\" and \"2\" to get \"4\". \r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4+%2B-+2%2Asqrt%2822%29%29%2F%284%29\" Simplify the square root \r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-4%2B2%2Asqrt%2822%29%29%2F%284%29\" or \"y+=+%28-4-2%2Asqrt%2822%29%29%2F%284%29\" Break up the expression. \r
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\n" ); document.write( "\n" ); document.write( "\"y+=+%28-2%2Bsqrt%2822%29%29%2F%282%29\" or \"y+=+%28-2-sqrt%2822%29%29%2F%282%29\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "So the solutions (for \"y\") are \"y+=+%28-2%2Bsqrt%2822%29%29%2F%282%29\" or \"y+=+%28-2-sqrt%2822%29%29%2F%282%29\"\r
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\n" ); document.write( "\n" ); document.write( "which approximate to \"y=1.35\" or \"y=-3.35\" \r
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\n" ); document.write( "\n" ); document.write( "Now plug these values into \"x%5E2=1%2F2%2By%5E2\" to find the corresponding \"x\" values. \r
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\n" ); document.write( "\n" ); document.write( "Note: You should get four ordered pair solutions (there are two x values for each y value you just found).
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