$2x+4=23$
Move the constant to the right-hand side and change its sign$2x=23-4$
Subtract the numbers$2x=19$
Divide both sides of the equation by $2$$\begin{align*}&x=\frac{ 19 }{ 2 } \\&\begin{array} { l }x=9 \frac{ 1 }{ 2 },& x=9.5\end{array}\end{align*}$