I need help with this question

Which triangle congruence postulate or theorem justifies my claim that the steps i made using construction paper and scissors produce an isosceles triangle? was it sss, sas, asa, aas, or hl?

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

If f(x)= sqrt4x+9+2, which inequality can be used to find the domain of f(x)?