The quantity demanded x of a certain brand of DVD player is 3000/week when the unit price p is $485. For each decrease in unit price of $20 below $485, the quantity demanded increases by 250 units. The suppliers will not market any DVD players if the unit price is $350 or lower. But at a unit price of $525, they are willing to make available 2500 units in the market. The supply equation is also known to be linear.

To find the supply equation, we can use the information given. We know that at a unit price of $525, the quantity supplied is 2500 units. We also know that the suppliers will not market any DVD players if the unit price is $350 or lower.

Let's assume the supply equation is in the form:

Qs = mP + b

where Qs is the quantity supplied, P is the unit price, m is the slope (rate of change of quantity with respect to price), and b is the y-intercept (quantity when the price is zero).

We can use the two points (525, 2500) and (350, 0) to find the slope (m) and the y-intercept (b) of the supply equation.

Using the slope formula:

m = (change in quantity)/(change in price)

m = (2500 - 0)/(525 - 350)
m = 2500/175
m = 14.286

Now that we have the slope (m), we can plug it into the equation:

Qs = 14.286P + b

Using the point (525, 2500), we can find the y-intercept (b):

2500 = 14.286(525) + b
2500 = 7500 + b
b = 2500 - 7500
b = -5000

Therefore, the supply equation for this particular DVD player is:

Qs = 14.286P - 5000