Question

if f(x)=x^2 find f(2-sqrt6)

Answer 1

Plug in 2-sqrt 6 where x goes, and perform the indicated operation. That meand, in this case, calculate
(2-sqrt6)^2.

You will learn much more by doing these yourself than by finding someone to do these problems for you.

Answer 2

I have the answer as 10-4sqrt6 is that right?

Answer 3

Yes!