x1 + x2 + 4x3 + 3x4 2x1 + 3x2 + x3 - 2x4 = 1 x1 + 2x25x3+4x4 = 5 = 3 Consider the following systems of equations and solve: A) It is a 3 times 4 system since it has 3 equations in 4 unknowns. Determine whether (a) (u=(-8,6,1,1) (b) (v=(-10,5,1,2)) are solutions of the system.