Question 765270
Solve the problem. 
The owner of a video store has determined that the cost C, in dollars, of operating the store is approximately given by c(x)= 2x^2 -26x+770 where x is the number of videos rented daily. Find the lowest cost to the nearest dollar.
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c(x)= 2x^2 -26x+770
This is an equation of a parabola that opens upward (function has a minimum)
Its standard form of equation: {{{y=A(x-h)^2+k}}}, k=minimum value 
complete the square:
c(x)= 2(x^2 -13x+169/4)-169/2+770
c(x)=2(x-13/2)^2+685.5
lowest cost=$686