Укажите область определения функции

A)y=(5-2x)/2
x∈R
b)y=2/(5-2x)
5-2x≠0
x≠5/2
x∈(-∞;5/2)U(5/2;∞)
c)y=5x²/(5-2|x|)
5-2|x|≠0
5-2x≠0 and 5+2x≠0
x≠-5/2 and x≠5/2
x∈(-∞;-5/2)U(-5/2;5/2)U(5/2;∞)