15. (10 pts) 1. Let V = R2, and define addition and scalar multiplication as follows: utv = (u1, U2) + (U1, U2) = (u101, u202) ku = k(u1, u2) = (up, u) Given that V is a vector space, (a) determine the value of 0 in V. (b) verify that k0 = 0 holds. (c) let u = (u1, u2) be in V. Find the value of -u such that u + (-u) = 0. (d) verify that (-1)u = -u holds