6. (U: 15, G: 15pts) Consider the minimization problem: minimize f(x) = x1 + x2 + 25 - 8x1 -62 subject to: x1 2 0, x2 20 Find the feasible directions for each of the points Xa = [0 3], x = [4 0], and Xc = [4 3] .L J ' |_ J 7. (U: 15, G: 15pts) For the previous problem, nd which if any of those points satisfy the second order necessary conditions for a local mini mum