Answer
$\text{Set Builder Notation: }
\left\{ n|n\ge-1.5 \right\}
\\\text{Interval Notation: }
\left[ -1.5,\infty \right)$
Work Step by Step
$\bf{\text{Solution Outline:}}$
Use the properties of inequality to solve the given inequality, $
1.8\ge-1.2n
.$ Write the answer in both set-builder notation and interval notation. Finally, graph the solution set.
In the graph, a hollowed dot is used for $\lt$ or $\gt.$ A solid dot is used for $\le$ or $\ge.$
$\bf{\text{Solution Details:}}$
Using the properties of inequality, the given equation is equivalent to
\begin{array}{l}\require{cancel}
1.8\ge-1.2n
\\\\
1.2n\ge-1.8
\\\\
10(1.2n)\ge10(-1.8)
\\\\
12n\ge-18
\\\\
n\ge-\dfrac{18}{12}
\\\\
n\ge-\dfrac{3}{2}
\\\\
n\ge-1.5
.\end{array}
Hence, the solution set is
\begin{array}{l}\require{cancel}
\text{Set Builder Notation: }
\left\{ n|n\ge-1.5 \right\}
\\\text{Interval Notation: }
\left[ -1.5,\infty \right)
.\end{array}