Find formulas for X, Y, and Z in terms of A, B, and C. It may be necessary to make assumptions about the size or invertability of a matrix in order to produce a formula. [Hint: Compute the product on the left, and set it equal to the right side.]

Problem number 26 of the rhind papyrus says: find a quantity such that when it is added to of itself the result is a 15. the modern day equation that models this problem is x + x = 15. what is the solution to the equation? x = 10 x = 12 x = 15 x = 30