Question 2302
You can graph this or use the "complete the square" (CTS) method.  I'll do both.  I won't go into detail how to "complete the square" but rather show my steps.  If you're not familiar with CTS, write back and I'll tell you.
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R(x)=140x-.02x^2
y=-.02x^2+140x
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Factor out the -.02
{{{y = -.02(x^2-7000x)}}}
{{{y=-.02(x^2-7000x+12250000)+245000}}}
{{{y=-.02(x-3500)^2+245000}}}
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This is now in the form of: {{{y=a(x-h)^2+k}}}, where (h,k) is the vertex.  "k" is the maximum if "a" is negative.  "k" is the minimum if "a" is positive.
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So, (3500, 245000) is the vertex.
<b>245000 is the maximum</b>
Here is the graph to prove my statements.
{{{graph( 600, 400, -9000, 15000, -14000, 280000, -(1/50) x^2+140*x)}}}
MS