Question

What is the interval notation for the graph shown below?

Answer 1

Answer: Bottom left corner (southwest corner)

$(4, \infty)$

The left endpoint is x = 4, but we don't include this endpoint because of the open hole. We use a parenthesis to indicate "don't include the endpoint"

The right endpoint is positive infinity. We always use a parenthesis with either infinity since we cannot reach infinity

The interval from 4 to infinity is written as $(4, \infty)$ which is like saying $4 < x < \infty$