need help with this question

Question 4 Consider the following bilinear from on R3, B(x, y) = 51 + 3.121/1 + 3431/1 + 3,1/2 + 421/2 + 3531/2 + 3513 + 35213 + 531/3, where r = (11, 12, 13) and y = (1/1, 1/2, Va) are vectors in Ra. (a) [3 Marks] Find the matrix representation of B(r, y) with respect to the standard basis {el, ez, (3} of IR3. (b) [4 Marks] Looking at part (c) of Question 3, find a basis y of Ra such that B(r,y) is represented by a diagonal matrix with respect to y