Step-by-step explanation:
the 2 solutions to any quadratic equation
ax² + bx + c = 0
are
x = (-b ± sqrt(b² - 4ac))/(2a)
in our case
a = 12
b = 1
c = -1
x = (-1 ± sqrt(1² - 4×12×-1))/(2×12) =
= (-1 ± sqrt(1 + 48))/24 = (-1 ± sqrt(49))/24 =
= (-1 ± 7)/24
x1 = (-1 + 7)/24 = 6/24 = 1/4 = 0.25
x2 = (-1 - 7)/24 = -8/24 = -1/3 = -0.33333333...
