Is $\frac{s^{-1}+z^{-1}}{s^{-4}-z^{-4}}=\frac{s-z}{s+z}$ A True Statement? Explain Your Answer by Simplifying the Expression

Essay

Is $\frac{s^{-1}+z^{-1}}{s^{-4}-z^{-4}}=\frac{s-z}{s+z}$ a true statement? Explain your answer by simplifying the expression on the left, step by step, until it is an expression with only positive exponents that cannot be further simplified.