212. $x=\frac{a^{2}(a+b)^{3}}{(a-b)^{2} c^{3}}$.

212. $x=\frac{a^{2}(a+b)^{3}}{(a-b)^{2} c^{3}}$.
Solution. Applying theorems 2,1 and 3, we get

$\log x=\log \left[a^{2}(a+b)^{3}\right]-\log \left[(a-b)^{2} c^{3}\right]=\log a^{2}+\log (a+b)^{3}-\log (a-b)^{2}-$

$$
-\log c^{3}=2 \log a+3 \log (a+b)-2 \log (a-b)-3 \log c
$$