Question 821616
You ask too many at once, but I will help with #1.


Putting this into logarithm form, assuming all still in base 10,
{{{log(10,3)=log(10,x^2-6)}}}
If these two logarithms are equal, then so must be their arguments, so we have
{{{3=x^2-6}}}
{{{x^2=3+6}}}
{{{x^2=9}}}
{{{x=3}}} or {{{x=-3}}}


I would give advice on #2, but I can't exactly read what you mean.  It could appear more precise if done on paper.