Apply the method in Exercise 5.5.22 to find the least squares solutions to the systems in Exercise 4.3.14.
(a) x + 2y = 1, 3x - y = 0, - x + 2y = 3,
(b) 4x - 2y = 1, 2x + 3y = - 4, x - 2y = - 1, 2x + 2y = 2,
(c) 2u + v - 2w = 1, 3u - 2w = 0, u - v + 3w = 2,
(d) x - z = - 1, 2.x - y + 3z = 1, y - 3z = 0, - 5x + 2y + z = 3,
(e) x1 + x2 = 2, x2 + x4 = 1, x1 + x3 = 0, x3 - x4 = 1, x1 - x4 = 2.