Answer
$x\gt-4$
Work Step by Step
Using the properties of inequality, the solution to the given inequality, $
2.1x+43.2\gt1.2-8.4x
,$ is
\begin{array}{l}\require{cancel}
2.1x+8.4x\gt1.2-43.2
\\\\
10.5x\gt-42
\\\\
x\gt-\dfrac{42}{10.5}
\\\\
x\gt-4
.\end{array}