Step-by-step explanation:
x² + 2x - 5 = 0
that is the same as
x² + 2x + 1 = 6
(x + 1)² = 6
x + 1 = ±sqrt(6)
x = -1 ± sqrt(6)
x1 = -1 + sqrt(6)
x2 = -1 - sqrt(6)
n² - 20n + 2 = 4
this is the same as
(n - 10)² = 102
n - 10 = ±sqrt(102)
n = 10 ± sqrt(102)
n1 = 10 + sqrt(102)
n2 = 10 - sqrt(102)