Question 4: [10 +11 Marks] [CLO4] a: Show that rows and columns of the given matrix are orthogonal? 2 -1 6 √13 √5 √39 3 -2 7 L = √13 √ √√39 -3 8 √13 √5 √39 b: Construct the orthogonal basis of set T= {v1, v2, v3} for R³ Where V₁ = 9 V₂ = √3 = Express the vector y as a linear combination of the vectors in T. y=7 and also show that the set T is an orthonormal basis in R³.