a) \(x\in B\left(12\right);20< x\le50\)
\(x\in\left\{24;36;48\right\}\)
d) \(x⋮12;x\le60\)
\(x\in\left\{0;12;24;36;48;60\right\}\)
g) \(\left\{{}\begin{matrix}x⋮25=5^2\\x⋮90=2.3^2.5\end{matrix}\right.\)
\(\Rightarrow x=2.3^2.5^2=450\)
\(\Rightarrow x\in\left\{0;450\right\}\)
