Answer
\[m=\frac{E}{{{c}^{2}}}\].
Work Step by Step
The provided formula is\[E=m{{c}^{2}}\]and now solve the formula for \[m\] by dividing both the sides by \[{{c}^{2}}\]
\[\begin{align}
& E=m{{c}^{2}} \\
& \frac{E}{{{c}^{2}}}=\frac{m{{c}^{{}}}}{{{c}^{{}}}} \\
& m=\frac{E}{{{c}^{2}}}
\end{align}\]
The formula \[E=m{{c}^{2}}\]is for energy of an object, where \[E=\] energy, \[m=\] mass of an object, and\[c=\] speed of the light.
The formula is\[m=\frac{E}{{{c}^{2}}}\].
