Y " C ` I ` G0 C " 5 ` 0.5Y I " 10 ´ 0.10R0 where government purchases, G0, and the real interest rate, R0, are exogenous, and Y , C, and I are the endogenous variables that we need to solve for. (a) Setup the system of equations with the terms with the endogenous variables on the left hand side of each equation, and the terms with the constants and the exogenous variables on the right hand side. (b) Now form the coefficients' matrix A, the variables' vector x, and the constants' vector d. The constants' vector will have the constant terms and the exogenous variables terms. (c) Use Cramer's rule to find Y ˚ , C ˚ , and I ˚ . These should be functions of the exogenous variables, G0 and R0.