Solve the following equations:
$\begin{array}{l}
x+3=7 \\
\frac{x}{3}=7 \\
3x+1=13 \\
10x-15=4x+27
\end{array}$
$\begin{array}{l}
x+3=7 \\
\frac{x}{3}=7 \\
3x+1=13 \\
10x-15=4x+27
\end{array}$