Why can you simplify square root of (X + 2) squared and NOT square root of Xsquared + 4?
If you could help it would be greatly appreciated. :)

If you square a quantity and then take the square root you get the original number back - actiually the positive an negative values of that number. So for example 4 squared is 16, and the square root of 16 is plus or minus 4. So in your first example, you square a quantity (x+2) to get (x+2)^2, then take its square root and you get plus or minus (x+2). In your second example x^2+4 is not a square- it's the sum of two squares, but in general the sum of two squares is not itself a square. So the square root of (x^2+4) can't really simplified.