Transform an implicit demand function into explicit linear demand function.

In the implicit demand function,

Q^d = f(P)

To transfer it into an explicit linear demand function, we introduce parameters,

Q^d = a - bP,

where a and b are parameters and a, b > 0.

a is a finite value which indicates that at price = 0, consumers will buy a amount of goods.

-b is known as the slope of the function.

-b = $\frac{Q_2^d \, - \, Q_1^d}{P_2 \, - \, P_1}$

A negative sign shows that when price increases, quantity demand decreases.