Question

f(x)= Radical (8-x) find domain in intervals

Answer 1

You take the (8-x) and set it greater than or equal to 0 and then solve for x. This is done because you cannot have a 0 inside of a radical so your answer should look like this
(-infinity, -8)u(-8, infinity). Note I used parenthesis because 8 is not included and infinities are always written with them.