How do I anwser this Imao

Explain why the function is discontinuous at the given number a. (select all that apply.) f(x) = 1 x + 1 a = −1 f(−1) is undefined. lim x→−1+ f(x) and lim x→−1− f(x) exist, but are not equal. lim x→−1 f(x) does not exist. f(−1) and lim x→−1 f(x) exist, but are not equal. none of the above

Identify the polynomial. a2b - cd3 a. monomial b. binomial c. trinomial d. four-term polynomial e. five-term polynomial

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?