Answer
It is necessary to change the direction of the inequality symbol when both sides of an inequality get multiplied or divided by a negative number to solve the inequality.
Work Step by Step
Suppose to solve inequality \[-3x<21\], the steps are:
\[-3x<21\]
Now, divide both sides by \[-3\], so:
\[\begin{align}
& \frac{-3x}{-3}>\frac{21}{-3} \\
& x>-7
\end{align}\]
In the above inequality, the sign is reversed because it is divided by \[-3\].
