Show that the following mappings are not LINEAR:
(a) F: R2 → R2 defined by F(x, y) = (x2, y2)
(b) F: R3 → R2 defined by F(x, y, z) = (x + 1, y+z)
(c) F: R2 → R2 defined by F(x,y) = (xy, y)
(d) F: R3 → R2 defined by F(x, y, z) = ([xl, y + 2)