I don't know if this is the full answer but the calculator says 1.732050808 and that is as far as it goes, even if it is not complete. Hope this helps a little bit.
The answer is radical 3. This is because you must rationalize the irrational denominator by multiplying the numerator and denominator of the original fraction by radical 3. (Multiply the fraction by radical 3 / radical 3.) The end result is 3 radical 3 over 3. You then simplify the 3's through simple division (3/3 = 1) and there is your answer, radical 3. Radical 3's decimal is computed by the calculator as 1.732..... and so on, but in reality this number is never as precise as radical 3 is because it is rounded.
36
1.7778
1.7778
18
There is no square root of -75. If it's 75, that is 5 square root 3.
2 times the Square root of 3 + 4
Square root (75) / square root (3) = 5
81
3
3.46410162
1.3333
36
root 27 = root 9 x root 3 = 3 root 3. Dividing this by root 3 gives 3!
Square root 1/483 = .0455
1.7778
99982/3
3