Solve the following equation with unknown \(x\) and a real parameter \(a\in\mathbb{R}\setminus\{-3,3\}\).
\[\frac{a-x} {a-3} - \frac{6a} {a^{2}-9} = \frac{x-3}
{a+3} \]
Identify a set of the values of the real parameter
\(m\) which
ensure that the equation
\[
\frac{m}
{x} - 8 = \frac{1}
{x} -\frac{m + 3}
{2}
\]
has solution \(x = 2\).
Identify the set of the values of the real parameter \(d\) for which the following equation has no solution in \(\mathbb{R}\).
\[
x^{2} - 2dx + 2d^{2} - 9 = 0
\]
Identify the set of the values of the real parameter \(t\) for which the following equation has two different real roots.
\[
x^{2} + (t + 2)x + 1 = 0
\]