Question 134543
Given : {{{R=1400x-5x^2}}} 
what number of items would provide a revenue of $16,080?

{{{R=1400x-5x^2}}} 
{{{16080 = 1400x-5x^2}}} 
{{{3216 = 280x - x^2}}}
{{{0 = x^2 - 280x + 3216}}}


Use the quadratic equation
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}}

(280 -+ 256)/2
x = 12 , 268

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