Nigel runs a pet grooming service. His fixed costs are $⁢600 per month, and it costs $⁢12 per pet groomed. The revenue is $⁢0 when no pets are groomed and $⁢0 when 100 pets are groomed due to market saturation. The maximum revenue occurs when 50 pets are groomed. Write a system of equations for the linear cost function, C⁡(x) , and a quadratic revenue function, R⁡(x) , where x represents the number of pets groomed.