Need help with some math hw - sqrt inside a sqrt

[cw42]

i been trying to figure out how this problem simplifies...

sqrt( 46 - 6sqrt(5) ) = 3sqrt(5) - 1

how did the first part simplify into the second?

 

[dym]

Originally posted by: cw42
i been trying to figure out how this problem simplifies...

c= 3sqrt(5) - 1

how did the first part simplify into the second?

sqrt( 46 - 6sqrt(5) ) =sqrt( (3sqrt(5) -1)^2 ) (perfect square)

does that help?