Modified SMO 2017 Open problem Question 1, Emphasis on finding the domain of function first

Find the last digit of (√(x^2-49)+√(49-x^2 ))/|x-7| +(13+x)^2024∀ x∈R s.t.(√(x^2-49)+√(49-x^2 ))/|x-7| +(13+x)^2024 ∈ R. Mathematician Ng Bee Yong posted answers on family blog. Another math competition "year problem".
This problem appears absurdly difficult or even ill-posed (Erin Pearse)until one realizes function has a singleton domain of x=-7 {-7} and more importantly a singleton range of 6^2024 possessing a trivial last digit!
Mariano Suárez-Álvarez has no interest in anecdotes about famous math icons.