Find the number of positive integers with three mutually different digits which can be written just
using the digits \(2\),
\(3\),
\(4\),
\(5\) and which can
be divided by \(3\).
Find the number of positive integers with three mutually different digits which can be written just
using the digits \(2\),
\(3\),
\(4\),
\(5\) and which can
be divided by \(4\).
Find a set of the values of the real parameter
\(a\) which
ensure that the following equation has a unique solution.
\[
a^{3}x + 4a - 1 = a^{2}x + 3
\]
Find the number of mutually different isosceles triangles (at least
two sides are equal) such that each side of each triangle is either
\(2\),
\(3\),
\(4\) or
\(5\).