Question 216519
For problems like this, just plug in the given value for x and solve the equation:
{{{g(x)=sqrt(x^2-25)}}}
{{{g(-6)=sqrt((-6)^2-25)}}}
{{{g(-6)=sqrt(36-25)}}}
{{{g(-6)=sqrt(11)}}}
I will leave the other 3 to you.
===============
Good Luck,
tutor_paul@yahoo.com