When finding the domain of rational and square root functions, how do you know when to plug in numbers to see if points will be positive and negative and when you don't have to?

Figure abcd is a parallelogram. if point c lies on the line x = 2, what is the y-value of point c?

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

Bernice paid $162 in interest on a loan of $1800 borrowed at 6%. how long did it take her to pay the loan off?