document.write( "Question 1162042: Given the function f(x)=-2c+cx-x^2 and f^-1(3)=-1, find c. \n" ); document.write( "
Algebra.Com's Answer #785729 by MathLover1(20849)\"\" \"About 
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\n" ); document.write( "Given the function \"f%28x%29=-2c%2Bcx-x%5E2\" and \"f%5E-1%283%29=-1\", find \"c\"\r
\n" ); document.write( "\n" ); document.write( "first find inverse\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=y\"\r
\n" ); document.write( "\n" ); document.write( "\"y=-2c%2Bcx-x%5E2\" ...swap variables\r
\n" ); document.write( "\n" ); document.write( "\"x=-2c%2Bcy-y%5E2\"..........complete square\r
\n" ); document.write( "\n" ); document.write( "\"x=-2c%2B%28b%5E2%2Bcy-y%5E2%29-b%5E2\" ->\"b=c%2F2\"\r
\n" ); document.write( "\n" ); document.write( "\"x=-2c%2B%28%28c%2F2%29%5E2%2Bcy-y%5E2%29-%28c%2F2%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2B2c%2B%28c%2F2%29%5E2+=%28c%2F2-y%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"x%2B2c%2Bc%5E2%2F4+=%28c%2F2-y%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%28x%2B2c%2Bc%5E2%2F4%29+=c%2F2-y\"\r
\n" ); document.write( "\n" ); document.write( "\"y=+c%2F2-sqrt%28x%2B2c%2Bc%5E2%2F4%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%5E-1=+c%2F2-sqrt%28x%2B2c%2Bc%5E2%2F4%29\"\r
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\n" ); document.write( "\n" ); document.write( "if \"f%5E-1%283%29=-1\", means if \"x=3\" then \"y=-1\"\r
\n" ); document.write( "\n" ); document.write( "\"-1=+c%2F2-sqrt%283%2B2c%2Bc%5E2%2F4%29\"\r
\n" ); document.write( "\n" ); document.write( "\"sqrt%283%2B2c%2Bc%5E2%2F4%29=+c%2F2%2B1\"....square both sides\r
\n" ); document.write( "\n" ); document.write( "\"3%2B2c%2Bc%5E2%2F4=+%28c%2F2%2B1%29%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"3%2B2c%2Bc%5E2%2F4=+c%5E2%2F4%2B2%28c%2F2%29%2B1\"....simplify\r
\n" ); document.write( "\n" ); document.write( "\"3%2B2c=+c%2B1\"\r
\n" ); document.write( "\n" ); document.write( "\"2c-c=1-3\"\r
\n" ); document.write( "\n" ); document.write( "\"c=-2\"\r
\n" ); document.write( "\n" ); document.write( "so, \"f%28x%29=-2c%2Bcx-x%5E2\" is\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=-2%28-2%29%2B%28-2%29x-x%5E2\"\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=4-2x-x%5E2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "and\r
\n" ); document.write( "\n" ); document.write( "\"f%5E-1%28x%29+\"will be\r
\n" ); document.write( "\n" ); document.write( "\"f%5E-1=+-2%2F2-sqrt%28x-4%2B1%29\"\r
\n" ); document.write( "\n" ); document.write( "\"f%5E-1=+-1-sqrt%28x-3%29+\"-> check result if \"x=3\", \"f%5E-1=+-1\"\r
\n" ); document.write( "\n" ); document.write( "\"-1=+-1-sqrt%283-3%29\"\r
\n" ); document.write( "\n" ); document.write( "\"-1=+-1-sqrt%280%29\"\r
\n" ); document.write( "\n" ); document.write( "\"-1=+-1\"->true\r
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