$$ \begin{aligned} 13 &= 2x+5&& \text{ swap the left and right side of the equation } \\[1 em]2x+5 &= 13&& \text{ move 5 to the right } \\[1 em]2x &= 13-5&& \\[1 em]2x &= 8&& \text{ divide both sides by $ 2 $ } \\[1 em]x &= \frac{8}{2}&& \\[1 em]x &= 4&& \\[1 em] \end{aligned} $$