How do you solve an infinite surd?

If an infinite surd is like (√(6+√(6+√(6+√(6...),to solve it, follow these steps:

Set x = √(6+√(6+√(6+√(6...

therefore x2 = 6+√(6+√(6+√(6+√(6...

therefore x2 = 6+x

therefore 6+x-x2 = 0.

Factorising the expression gives you (-x+3)(x+2)=0

Only the positive answer need be concerned with:

-x+3=0

therefore -x = -3

therefore x = 3.