A=12^36:36^18, b=12^35:36^17

[latex]a= \frac{12^{36}}{36^{18}}= \frac{(2\cdot6)^{36}}{(6\cdot6)^{18}} = \frac{2^{36}\cdot 6^{36}}{6^{18}\cdot6^{18}}= \frac{2^{36}\cdot 6^{36}}{6^{18+18}}=2^{36} \\ \\ b= \frac{12^{35}}{36^{17}}= \frac{(2\cdot6)^{35}}{(6\cdot6)^{17}}= \frac{2^{35}\cdot6^{35}}{6^{17}\cdot6^{17}}= \frac{2^{35}\cdot6^{35}}{6^{17+17}}= \frac{2^{35}\cdot6^{35}}{6^{34}}= 2^{35}\cdot6= \\ \\= 2^{36}\cdot 3 \ \textgreater \ 2^{36}=a [/latex]