Final answer:
The actual math problem in the question could not be solved due to lack of context. However, the economics problem involving quantity demanded and supplied can be solved using algebra, setting 16 - 2P equal to 2 + 5P to find the equilibrium price and quantity, which are $2 and 12 units, respectively. Alternatively, graphing the demand and supply curves can also yield the same result.
Step-by-step explanation:
The original question seems to contain a mistake or typo, as it mentions values for QB and BC but asks for QD without providing context or a figure that we could refer to for geometry or algebra. It seems that, inadvertently, a portion of an economics problem dealing with quantity demanded and quantity supplied in a market and their relationship to price was included instead.
However, if we were to solve the provided economics problem, we can find the equilibrium price and quantity by setting the quantity demanded (Qd) equal to the quantity supplied (Qs), which is represented by the equations 16 - 2P = 2 + 5P. Adding 2P to both sides and subtracting 2 from both sides of the equation yields 14 = 7P. Dividing both sides by 7 gives us P = 2. Once we have the price, we can plug it back into either the demand or supply equation to find that the equilibrium quantity (Q) is 12.
Alternatively, to graphically find the equilibrium, we would plot the demand curve P = 8 - 0.5Qd and the supply curve P = -0.4 + 0.2Qs on a graph with price on the vertical axis and quantity on the horizontal axis. The intersection point of the two curves gives us the equilibrium price and quantity which in this case would be $2 and 12 units, respectively.