Question 1041311
The cost function is not involved in finding max x for the revenue function.  You have two separate functions, R for revenue and C for cost.  


Where is R a maximum value?
Between the zeros in the exact middle.
{{{68x-2x^2=0}}}
{{{34x-x^2=0}}}
{{{x(34-x)=0}}}
Zeros are at 0 and at 34.  The maximum occurs exactly between these two values!