Rules for Surds

(1)  √a x √a = a                    e.g. √7 x √7 = 7

(2)  √a x √b = √ab                e.g.  √5 x √2 = √10

(3)  √a ÷ √b = √a/b              e.g. √10 ÷ √2 = √10/2 = √5

(4)  x√a x y√b = xy√ab         e.g. 2√7 x 3√2 = 6√14

(5)  x√a ÷ y√b = x/y√a/b      e.g. 12√6 ÷4√3 = 12/4√6/3 = 3√2