Question

х²=7√7√7√7√7... и т.д.

Answer 1

$x=\pm \sqrt{7 \sqrt{7 \sqrt{7 \sqrt{7... } } } }=\pm 7^{1/2}\cdot7^{1/2^2}\cdot 7^{1/2^3}\cdot 7^{1/2^4}\cdot\ldots=\\ =\pm7^{1/2+1/2^2+1/2^3+1/2^4+\ldots}=\pm 7.$