Please Help I don't get this

Answer:
The choose (D)
Step-by-step explanation:
[tex] \frac{x - 16}{ {x}^{2} + 6x - 40 } + \frac{1}{x + 10} \\ = \frac{x - 16}{(x - 4)(x + 10)} + \frac{1}{x + 10} \\ = \frac{(x - 16) + (x - 4)}{(x + 10)(x - 4)} \\ = \frac{2x - 20}{(x + 10)(x - 4)} \\ = \frac{2x - 20}{ {x}^{2} + 6x - 40 } [/tex]