document.write( "Question 50513: Hi, the following question I dont know where to start with:
\n" ); document.write( "it is the daily profit for whitegoods store from sale of bar fridges is given by P(x)= -x^2+40x+825 where x is number of bar fridges sold. Find the function's vertex and intercepts.
\n" ); document.write( "Thanks very much if you could please help me with this one! \n" ); document.write( "
Algebra.Com's Answer #33598 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
P(x)= -x^2+40x+825
\n" ); document.write( "Rewrite as follows:
\n" ); document.write( "-(x^2-40x+?)= P(x)-825+?
\n" ); document.write( "Complete the square to get:
\n" ); document.write( "-(x^2-40x+400) = P(x)-825-400
\n" ); document.write( "-(x-20)^2 = P(x)-425
\n" ); document.write( "This follows the form y-k=(x-h)^2
\n" ); document.write( "where (h,k) is the vertex.
\n" ); document.write( "For your problem h=20,k=425
\n" ); document.write( "Vertex is (20,425).
\n" ); document.write( "---------
\n" ); document.write( "To find the y-intercept let x=0 in the original equation.
\n" ); document.write( "Then P(0)=825.
\n" ); document.write( "So, y-intercept is (0,825)
\n" ); document.write( "---------
\n" ); document.write( "To find the x-intercepts use the quadratic formula.
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "
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