0.125 in a fraction form 

0.125

= 0.100 + 0.020 + 0.005

= 0.1 + 0.02 + 0.005

= 1/10 + 1/50 + 1/200

= 20/200 + 4/200 + 1/200

= 25/200

= 1/8

For the first 3 you just have to divide (forget about the square root for now) and then reduce its result by finding two numbers (one of them have to be able to be squared rotted) that multiplied gives the fist result. Then you just have to square root one of the numbers and leave the other one as it is.

For the last 4; you cannot have radicals in the denominator, so you have to multiply both top and bottom by the square root, after that you just reduce.

Hope you understand, if you have any questions please let me know.