Step-by-step explanation:
Root of the function, where y = 0
f(x) = x² + 2x - 1
0 = x² + 2x - 1
x² + 2x - 1 = 0
x² + 2x = 1
x² + 2x + 1 = 1 + 1
(x + 1)² = 2
x + 1 = ±√2
x = -1 ± √2
Roots → x = -1 ± √2
