Question

If f(x)= x2 - 4x - 4, find the input values that make the function 0.

Answer 1

Step-by-step explanation:

f(x) = x² - 4x - 4

the general formula for solving such a quadratic equation (for f(x) = 0) is

x = (-b ± sqrt(b² - 4ac))/(2a)

in our case

a = 1

b = -4

c = -4

x = (4 ± sqrt(4² - 4×1×-4))/(2×1) = (4 ± sqrt(16 + 16))/2 =

= (4 ± sqrt(2×16))/2 = (4 ± 4×sqrt(2))/2 = 2 ± 2×sqrt(2)

x1 = 2 + 2×sqrt(2)

x2 = 2 - 2×sqrt(2)