In each case show that B is an orthogonal basis of R3 and use Theorem 6 to

Question:

In each case show that B is an orthogonal basis of R3 and use Theorem 6 to expand X = [ a b c]T as a linear combination of the basis vectors.
(a) B = {[1 -1 3]T,[-2 1 1]T, [4 7 1]T}
(b) B = {[1 0 -1]T,[1 4 1]T, [2 -1 2]T}
(c) B = {[l 2 3]T,[-l -1 ]T, [5 -4 l]T}
(d) B = {[1 1 1}T,[1 -1 0}T,[1 1 -2]T}