document.write( "Question 604580: f(x)= 3(x^2+5) Find f^-1(x), f^-1(27) \n" ); document.write( "

Algebra.Com's Answer #381273 by nerdybill(7384) $\"\"$ $\"About$

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f(x)= 3(x^2+5) Find f^-1(x), f^-1(27)
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\n" ); document.write( "Find f^-1(x):
\n" ); document.write( "y = 3(x^2+5)
\n" ); document.write( "switch the variables and solve for y:
\n" ); document.write( "x = 3(y^2+5)
\n" ); document.write( "x/3 = y^2+5
\n" ); document.write( "x/3 - 5 = y^2
\n" ); document.write( "sqrt(x/3 - 5) = y
\n" ); document.write( "or
\n" ); document.write( " $\"f%5E-1%28x%29+=+sqrt%28x%2F3+-+5%29\"$
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\n" ); document.write( "finding f^-1(27):
\n" ); document.write( " $\"f%5E-1%28x%29+=+sqrt%28x%2F3+-+5%29\"$
\n" ); document.write( " $\"f%5E-1%2827%29+=+sqrt%2827%2F3+-+5%29\"$
\n" ); document.write( " $\"f%5E-1%2827%29+=+sqrt%289+-+5%29\"$
\n" ); document.write( " $\"f%5E-1%2827%29+=+sqrt%284%29\"$
\n" ); document.write( " $\"f%5E-1%2827%29+=+2\"$ (that's plus or minus 2)
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