A2. The equation $\log \left(m^{2}-3 m\right)=1$ has solutions:
(A) 0 and 3
(B) 5 and -2
(C) -5 and 2
(D) $\pm \frac{1}{2}$
(E) The equation is not solvable.
A2. In the equation, the logarithm with base 10 appears, so we can write $10=m^{2}-3 m$. We rearrange the equation: $m^{2}-3 m-10=0$, factorize and get the solutions $m_{1}=5, m_{2}=-2$.