Answer:
The cost for a 2,000 square foot house is 
Detailed explanation:
Recall that if two variables x and y vary directly, the relationship can be written as
or
.
Define:
x as the house area in square feet
y as the price of the house
Given point (1500, 300000)
Calculate proportionality constant k:

Insert values:

The direct variation equation is:

For x = 2000:
Calculate y:
Replace x in equation:

