4. Let (f: E) be a 2 x 2 matrix. 1') Show that swapping the columns of the matrix multiplies the determinant by 1. That is, Show that a b b a that (r: d) = dEt (a! c) it} Show that adding a multiple of one eelunm to another does not change the determinant. i.e. for all J. E R: a b a b + la det (e d) _ det (e d + in)