convolution-summation

Verify the distributive and associative properties of convolution-summation x(n) * (h1(n) + h2(n)) = x(n) * h1(n) + x(n) * h2(n) and x(n) * (h1(n) * h2(n)) = (x(n) * h1(n)) * h2(n) where {h1(n), n = 0, 1, 2, 3}={1, 2, 3, 4}, {h2(n), n = 0, 1, 2, 3} = {3, 2, 1, 5}, and {x(n), n = 0, 1, 2, 3}={4, 4, 3, 2}.