Question

Express the set W = { z ∣ z ≤ − 2 or z ≥ 10 } W={z∣z≤-2orz≥10} using interval notation

Answer 1

The answer is $(-\infty, -2] \cup [10, \infty)$

The first portion $(-\infty, -2]$ represents the inequality $z\le-2$

The second portion $[10, \infty)$ represents the inequality $z\ge10$

The big U symbol is the union symbol to effectively glue the two intervals together.