Question

х квадрат - 2х - 5 = 0

Answer 1

x² - 2x - 5 = 0 
D = 4 + 20 = 24 = ( 2√6 )²
x1 = ( 2 + ( 2√6 )) : 2 = 1 + √6 
x2 = 1 - √6