2. consider a system of two equations in two unknowns: (a) solve this system to produce formulas for the value of r and y (b) let a be the coefficient matrix; a be the matrix produced by replacing first column of the coefficient matrix (corresponding to the variable ) with the constant vector; a, be the matrix pro- duced by replacing the second column of the coefficient matrix (corresponding to the variable y) with the constant vector. find det a, det a, and det a (c) express the values of r and y in terms of these determinants. (this gives a result generally known as cramer's rule)