In a perfect competition, the demand function of a commodity is \( Q_{d}=20-3 \mathrm{p}-p^{2} \) and the supply function is \( Q_{s}=5 \mathrm{p}-1 \), where p is price, \( Q_{d} \) and \( Q_{s} \) are quantity demanded and quantity supplied respectively. Specify the domain and range of the both functions.
