Why is this true 9a=11a-2a​

List the elements of the set in roster notation. (enter empty or ∅ for the empty set.) {x | x is a letter in the word hippopotamus}

Recall the definition of a polynomial expression. find two polynomial expressions whose quotient, when simplified,is. use that division problem to determine whether polynomials are closed under division. then describe how theother three operations-addition, subtraction, and multiplication-are different from division of polynomials.

Sketch one cycle if the cosine function y=2cos2theta