algebra
posted by Jennifer .
Jane is taking a class and asks you to help her figure out what her last grade must be in the class to get a 85 in the class. She tells you the following calculation is used to find your final grade:
w2d2
x is her last score which has not been taken. Explain this equation and the process you would use to solve for the unknown test score. Solve for the test score.

Online "^" is used to indicate an exponent, e.g., x^2 = x squared.
I have no idea what w and d stand for to construct the equation.