If the supply function for a commodity is p = q2 + 6q + 16 and the demand function is p = −7q2 + 2q + 436, find the equilibrium quantity and equilibrium price.

equilibrium quantity = 7

equilibrium price = 107

Explanation:

Data provided in the question:

supply function, p = q² + 6q + 16  ........(1)

demand function is p = −7q² + 2q + 436

Now at equilibrium

Demand = Supply

Thus,

q² + 6q + 16 = −7q² + 2q + 436

or

q² + 6q + 16 + 7q² - 2q - 436 = 0

or

8q² + 4q - 420 = 0

or

2q² + q - 105 = 0

on solving for the roots of q

using the Quadratic Formula where

a = 2, b = 1, and c = -105

a = 2, b = 1, and c = -105

Thus,

The discriminant ( b² - 4ac > 0)

so, there are two real roots.

Therefore,

since,

Quantity cannot be negative

Thus,

q = 7

therefore, substituting q in (1)

p = 7² + 6(7) + 16

or

p = 49 + 42 + 16

or

p = 107

answer; competency based pay;