The sum of a number and four, multiplied by the sum of a number and five is equivalent to 13

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

Taking algebra two apex courses and need with these questions

Which region represents the solution to the given system of inequalities? |-0.5x+y23 | 1.5x+ys-1 5 4 -3 -2 -1 1 2 3 4