Sqrt242 can't be simplified anymore. It doesn't contain any perfect squares factors. For instance,

This can be simplified because

And 25 is a perfect square, and square root of 25 is 5. The simplified version for this would be 5 sqrt (6). For your question, sqrt 242 can't be simplified anymore, its most simplified version is its current state.
The equation of a circle is written as (x-h)^2 +(y-k)^2 = r^2
h is the x value of the center and k is the y value of the center and r is the radius.
Replace h, k and r with the given information:
(x- -7)^2 + (y - -6)^2 = 4^2
Simplify:
(x+7)^2 + (y+6)^2 = 16
9×10⁴ is 300 times greater than 3×10²
as, (9×10⁴)/(3×10²)=3× 10²
and the proper of writting powers in computer form is a×10^b