1. In real-world situations, what is the advantage of using the Method of Substitution to solve a system of equations rather than using the Method of Addition?
2. When solving a 3x3 determinant, we broke the determinant down into a sequence of 2x2 determinants, remembering to alternate the signs of the leading coefficients in front of these smaller determinants. By extension, how might you calculate a 4x4 determinant?