Answer
$m=-3$
Work Step by Step
$$\begin{align*}
10-7&=7-m-7 &\text{Subtract 7 from each side.}\\
3&=-m &\text{Simplify.}\\
3(-1)&=-m(-1) &\text{Multiply -1 to both sides.}\\
-3&=m &\text{Simplify.}\\
\end{align*}$$
Check the answer by substituting $-3$ to the variable in the given equation.
$$\begin{align*}
10&=7-m\\
10&\stackrel{?}{=}7-(-3)\\
10&\stackrel{?}{=}7+3\\
10&\stackrel{\checkmark}{=}10
\end{align*}$$
Thus, the solution is $m=-3$.
