Write the following systems of equations in matrix notation: x + y + z + t = a x + 3y + 2z + 4t = b (a 2x - 5x2 = 3 5x1 + 8x2 = 5 (b) (c) (a - 1)x + 3y - 2z = 5 ax + 2y – z=2 x - 2y + 32=1 x + 4y + 82 =C 2x + z