9.10. Suppose that & is a Lie algebra over C and that p is a symmetric, associative bilinear form of L. Show that 8 induces a linear map 0 : L-L*, 0(x) = B(x, -), where by B(I, -) we mean the map y -> B(r, y). Viewing both L and L as L-modules, show that 0 is an L-module homomorphism. (The L-module structure of L is given by Exercise 7.12.) Deduce that if B is non-degenerate, then L and L* are isomorphic as L-modules