Answer:
[tex] \frac{ {x}^{ - 1} + {y}^{ - 1} }{ {(x + y)}^{ - 1} } \\ \\ \frac{ \frac{1}{x} + \frac{1}{y} }{ {(x + y)}^{ - 1} } \\ \\ \frac{ \frac{1}{x} \times \frac{y}{y} + \frac{1}{y} \times \frac{x}{x} }{ {(x + y)}^{ - 1} } \\ \\ \frac{ \frac{y}{xy} + \frac{x}{xy} }{ {(x + y)}^{ - 1} } \\ \\ \frac{ \frac{y + x}{xy} }{ {(x + y)}^{ - 1} } \\ \\ \frac{y + x}{xy} \div {(x + y)}^{ - 1} \\ \\ \frac{y + x}{xy} \div \frac{1}{(x + y)} \\ \\ \frac{y + x}{xy} \times (x + y) \\ \\ = \frac{ {(x + y)}^{2} }{xy} [/tex]
I hope I helped you^_^
