document.write( "Question 1024212: the domain and range of f(x) = 2x to the power of two plus 8x-1 \n" ); document.write( "

Algebra.Com's Answer #639809 by Fombitz(32388) $\"\"$ $\"About$

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Convert to vertex form,
\n" ); document.write( " $\"f%28x%29=2x%5E2%2B8x-1\"$
\n" ); document.write( " $\"f%28x%29=2%28x%5E2%2B4x%29-1\"$
\n" ); document.write( " $\"f%28x%29=2%28x%5E2%2B4x%2B4%29-1-2%284%29\"$
\n" ); document.write( " $\"f%28x%29=2%28x%2B2%29%5E2-9\"$
\n" ); document.write( "The vertex is at ( $\"-2\"$ , $\"-9\"$ ) and the coefficient of the quadratic term is positive so the parabola opens upwards and the vertex value is a minimum.
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\n" ); document.write( "So the domain is all real numbers and the range is [ $\"-9\"$ , $\"infinity\"$ ).
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