5. Express these fractions as partial fractions \text { (a) } \frac{x^{2}+4}{3 x^{3}+4 x^{2}-4 x} \text { (b) } \frac{x^{2}-29 x+5}{(x-4)\left(x^{2}+3\right)} \text { (c) } \frac{x^{4}-5 x^{3}+6 x^{2}-18}{x^{3}-3 x^{2}}