You can use [Polynomial long division](https://en.wikipedia.org/wiki/Polynomial_long_division) to find the factors of this quartic equation...

But guessing in this case works too, and is faster :)

south_korea_ln

science

[Not-so-daily puzzle] Nested roots

Saw the hint before trying to solve all by myself :((

```
k = sqrt(7-sqrt(7+k))
k^2 = 7-sqrt(7+k)
sqrt(7+k) = 7-k^2
7+k = (7-k^2)^2
7+k = 49 - 14k^2 + k^4
k^4 - 14k^2 - k + 42 = 0
```
You can probably solve it analytically, but I quickly guessed k=2 looking at the numbers.
