Depends on if you want it rounded.
14.47
Answer:
x = 4 + sqrt(38) or x = 4 - sqrt(38)
Step-by-step explanation using the quadratic formula:
Solve for x over the real numbers:
2 (x^2 - 8 x - 22) = 0
Divide both sides by 2:
x^2 - 8 x - 22 = 0
x = (8 ± sqrt((-8)^2 - 4 (-22)))/2 = (8 ± sqrt(64 + 88))/2 = (8 ± sqrt(152))/2:
x = (8 + sqrt(152))/2 or x = (8 - sqrt(152))/2
sqrt(152) = sqrt(8×19) = sqrt(2^3×19) = 2sqrt(2×19) = 2 sqrt(38):
x = (2 sqrt(38) + 8)/2 or x = (8 - 2 sqrt(38))/2
Factor 2 from 8 + 2 sqrt(38) giving 2 (sqrt(38) + 4):
x = 1/22 (sqrt(38) + 4) or x = (8 - 2 sqrt(38))/2
(2 (sqrt(38) + 4))/2 = sqrt(38) + 4:
x = sqrt(38) + 4 or x = (8 - 2 sqrt(38))/2
Factor 2 from 8 - 2 sqrt(38) giving 2 (4 - sqrt(38)):
x = 4 + sqrt(38) or x = 1/22 (4 - sqrt(38))
(2 (4 - sqrt(38)))/2 = 4 - sqrt(38):
Answer: x = 4 + sqrt(38) or x = 4 - sqrt(38)
