Square Roots-Section 4.3
Simplifying expressions with square roots.
For video explanation see
https://www.khanacademy.org/math/algebra/exponent-equations/simplifying-radical-expressions/v/radical-equivalent-to-rational-exponents-2
or http://patrickjmt.com/radical-notation-and-simplifying-radicals/
or http://patrickjmt.com/radicals-simplifying-radical-expressions-involving-variables-ex-1/ (I can't use variables with GeoGebra for simplifying with variables).