How to solve the length of a side of a figure?

Use set builder notation to represent the following set: { -3, -2, -1, 0}

Find the domain of the following expression: 1/(√x)-2

*let m∠cob = 50°30’, m∠aob = 70° and m∠aoc = 20°30’. could point c be in the interior of ∠aob? why? a. point c could be the interior of aob but it is not the only case b. point c is the interior of aob c. point c is not the interior of aob d. the given is not possible for the plane geometry answer