document.write( "Question 1163385: The supply function qs = f (p) for a product is quadratic. Three points which lie on the supply function are (60, 2750), (70, 6000) and (80, 9750).\r
\n" ); document.write( "\n" ); document.write( "a) Determine the equation for the supply function
\n" ); document.write( "b) Make any observation you can about the restricted domain of the function
\n" ); document.write( "c) Compute and interpret the p intercept.
\n" ); document.write( "d) What quantity will be supplied at a price of $75
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Algebra.Com's Answer #787480 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "The function is quadratic:

\n" ); document.write( "\"q%28p%29+=+ap%5E2%2Bbp%2Bc\"

\n" ); document.write( "Use the three given points to form three equations in the unknowns a, b, and c.

\n" ); document.write( "\"3600a%2B60b%2Bc+=+2750\"
\n" ); document.write( "\"4900a%2B70b%2Bc+=+6000\"
\n" ); document.write( "\"6400a%2B80b%2Bc+=+9750\"

\n" ); document.write( "Eliminate c between the first and second equations, and between the second and third:

\n" ); document.write( "\"1300a%2B10b+=+3250\"
\n" ); document.write( "\"1500a%2B10b+=+3750\"

\n" ); document.write( "Eliminate b between those two equations:

\n" ); document.write( "\"200a+=+500\"
\n" ); document.write( "\"a+=+2.5\"

\n" ); document.write( "Plug a=2.5 in either of the previous two equations to find b=0.

\n" ); document.write( "Plug a=2.5 and b=0 in any of the original equations to find a=-6250.

\n" ); document.write( "a) ANSWER: The supply function is f(p) = 2.5p^2-6250

\n" ); document.write( "b) Mathematically, a negative price doesn't make sense -- so the restriction on the domain is p greater than or equal to 0.

\n" ); document.write( "But realistically a negative quantity supplied doesn't make sense either. f(50)=0, so realistically the restriction on the domain is p greater than or equal to 50.

\n" ); document.write( "c) The p-intercept is when q=0, which is (50,0). That means no products will be supplied when the price is $50.

\n" ); document.write( "d) q(75) = 7812.5. I'm not sure whether in the real world you would mean the quantity supplied at a price of $75 is 7812 or 7813....

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