Pls help and explain

Answer: [tex]\bold{-13\dfrac{9}{20}}[/tex] --> none of the answer choices are correct
Step-by-step explanation:
First, give each fraction a common denominator. Then add the integers and the fractions.
[tex]-5\dfrac{1}{4}-8\dfrac{1}{5}\\\\\\=-5\dfrac{1}{4}\bigg(\dfrac{5}{5}\bigg)-8\dfrac{1}{5}\bigg(\dfrac{4}{4}\bigg)\\\\\\=-5\dfrac{5}{20}-8\dfrac{4}{20}\\\\\\=-\bigg(5\dfrac{5}{20}+8\dfrac{4}{20}\bigg)\\\\\\=\large\boxed{-13\dfrac{9}{20}}[/tex]