document.write( "Question 128590: The given function is $\"f%28x%29=20000-15x\"$ \r
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\n" ); document.write( "\n" ); document.write( "Find $\"f%5E%28-1%29%2850%29\"$
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Algebra.Com's Answer #94079 by jim_thompson5910(35256) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"f%28x%29=20000-15x\"$ Start with the given function\r
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\n" ); document.write( "\n" ); document.write( "To find $\"f%5E%28-1%29%28x%29\"$ , simply swap x and f(x) to get \r
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\n" ); document.write( "\n" ); document.write( " $\"x=20000-15f%28x%29\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"15f%28x%29%2Bx=20000\"$ Add 15f(x) to both sides\r
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\n" ); document.write( "\n" ); document.write( " $\"15f%28x%29=20000-x\"$ Subtract x from both sides\r
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\n" ); document.write( "\n" ); document.write( " $\"f%28x%29=%2820000-x%29%2F15\"$ Divide both sides by 15 to isolate f(x)\r
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\n" ); document.write( "\n" ); document.write( "So the inverse function is $\"f%5E%28-1%29%28x%29=%2820000-x%29%2F15\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"f%5E%28-1%29%2850%29=%2820000-50%29%2F15\"$ Now plug in $\"x=50\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"f%5E%28-1%29%2850%29=%2819950%29%2F15\"$ Subtract\r
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\n" ); document.write( "\n" ); document.write( " $\"f%5E%28-1%29%2850%29=1330\"$ Divide\r
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