Simplify `(sqrt7+sqrt5)/(sqrt7-sqrt5)-(sqrt7-sqrt5)/(sqrt7+sqrt5)`

(sqrt7-sqrt6)/(sqrt7+sqrt6)-(sqrt7+sqrt6)/(sqrt7-sqrt6)=

Simplify (3+sqrt5)/(sqrt7-sqrt3)

Simplify (2/7-5/sqrt7)/(sqrt7-1/sqrt7)

Simplify each of the following : (i)(sqrt(2)+1)/(sqrt(2)-1)+(sqrt(2)-1)/(sqrt(2)+1)" "(ii)(sqrt(5)+sqrt(3))/(sqrt(5)-sqrt(3))+(sqrt(5)-sqrt(3))/(sqrt(5)+sqrt(3))" "(iii)(2)/(sqrt(5)+sqrt(3))+(1)/(sqrt(3)+sqrt(2))-(3)/(sqrt(5)+sqrt(2))" "(iv)(sqrt(7)+sqrt(5))/(sqrt(7)-sqrt(5))-(sqrt(7)-sqrt(5))/(sqrt(7)+sqrt(5))

Simplify (sqrt(7)-sqrt(5))/(sqrt(7)+sqrt(5))+sqrt(35)

sqrt(3)/(sqrt5+sqrt2-sqrt7)=

(7+sqrt(5))/(7-sqrt(5))-(7-sqrt(5))/(7+sqrt(5))=

7/(sqrt5-sqrt3) =

(sqrt(3)-sqrt(5))(sqrt(3)+sqrt(5))/(sqrt(7)-2sqrt(5))