Introduction to linear algebra (math 220, section 2) fall 2013. Brief solutions to practice midterm exam: (12) consider the following system of linear equations. 7x3 = (a) write the system as a matrix equation. 0 (b) write the system as a vector equation. x1 . 0 (c) write the augmented matrix for the system. 3 0 (a) solve the system ax = b, and write the solution in parametric vector form. R1 r2 x1 = 1 + x3 x2 = 2 + 2x3 x3 = x3 x4 = 3. The parametric vector form of the solutions is x = , s r. (b) using the result from part (a), write the solution to the homogeneous system ax = 0 in the parametric vector form. The parametric vector form of the solutions to ax = 0 is x = s. It can shown that 3u v = 2w.