## Precalculus (6th Edition)

Option $D$
The given inequality is "$6$ is less than or equal to $x$". This is equivalent to "$x$ is greater than or equal to $6$. The numbers included in this set are the numbers that are greater than or equal to $6$. The equivalent interval notation of the given inequality will have: $\bf\text{lower limit:}$ $6$, a bracket will be used since $6$ is included $\bf\text{upper limit:}$ none, so positive infinity will be used Therefore, the interval is: $\color{blue}{[6, +\infty)}$