У + 3x = -4 2х - Зу = -21
Help plz

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values

Use sigma notation to represent the following series for 9 terms.

What is the name of a polygon that has four congruent sides and theses angle measures 60,120,60,120?