document.write( "Question 1100684: If P(x) =5+8x-5x^2 represents the profit in selling x thousand Boombotix speakers, how many speakers should be sold to maximize profit? \n" ); document.write( "

Algebra.Com's Answer #715217 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+P%28x%29+=+-5x%5E2+%2B+8x+%2B+5+\"$
\n" ); document.write( "The x-value of the peak ( max profit ) is:
\n" ); document.write( " $\"+x%5Bmax%5D+=+-b%2F%282a%29+\"$
\n" ); document.write( " $\"+a+=+-5+\"$
\n" ); document.write( " $\"+b+=+8+\"$
\n" ); document.write( "----------------
\n" ); document.write( " $\"+x%5Bmax%5D+=+-8%2F%282%2A%28-5%29%29+\"$
\n" ); document.write( " $\"+x%5Bmax%5D+=+8%2F10+\"$
\n" ); document.write( " $\"+.8%2A1000+=+800+\"$
\n" ); document.write( "800 speakers should be sold
\n" ); document.write( "------------------------------
\n" ); document.write( "check:
\n" ); document.write( "Here's the plot
\n" ); document.write( "Plug $\"+x+=+.8+\"$ back into equation to get $\"+P%5Bmax%5D+\"$
\n" ); document.write( " $\"+graph%28+400%2C+400%2C+-1%2C+2%2C+-1%2C+10%2C+-5x%5E2+%2B+8x+%2B+5+%29+\"$
\n" ); document.write( " \n" ); document.write( "

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