$$ \begin{aligned} 6264-36 &= 12x&& \text{simplify left side} \\[1 em]6228 &= 12x&& \text{ swap the left and right side of the equation } \\[1 em]12x &= 6228&& \text{ divide both sides by $ 12 $ } \\[1 em]x &= \frac{6228}{12}&& \\[1 em]x &= 519&& \\[1 em] \end{aligned} $$