Radicals are numbers with roots. They get the nth root of a whole number.
Ex. [tex] \sqrt{8} =2 \sqrt{2} [/tex]
simplifying radicals (For extra info; applicable to roots)
You get the prime factorization of the number and if ever there is a number to the nth power then it will be outside the nth root sign and the remaining inside.
[tex] \sqrt[3]{16} =2 \sqrt[3]{2} [/tex]