Question

xy-4y=5x+3 determine domain in interval notation

Answer 1

first convert the equation equivalent to y
y(x-4)=5x+3
y=(5x+3)/(x-4)
for domain denominator must not br zero
so find the value at which it zero and exclude that value rest is your domain

Answer 2

x=4, (-infinite,4)u(4,infinite) then?

Answer 3

yeah now 4 and infinity can be included so use open bracket
(-infinity,4) u (4,infinity)