[tex]\bf \begin{cases}
3=a\cdot b^0\\
75=a\cdot b^2
\end{cases}\qquad b^0=1\implies
\begin{cases}
3=a\cdot 1\implies 3=a\\
----------\\
75=a\cdot b^2\implies 75=3\cdot b^2\\\\
\frac{75}{3}=b^2\implies 25=b^2\\\\
\pm \sqrt{25}=b\implies \pm 5 = b
\end{cases}[/tex]
recall, anything raised to the 0, zero, power, is 1, with the sole exception of 0
