$$ \begin{aligned} 52 &= -11a+48&& \text{ swap the left and right side of the equation } \\[1 em]-11a+48 &= 52&& \text{ move 48 to the right } \\[1 em]-11a &= 52-48&& \\[1 em]-11a &= 4&& \text{ divide both sides by $ -11 $ } \\[1 em]a &= -\frac{4}{11}&& \\[1 em] \end{aligned} $$