Solve 2x2 + 20x + 8 = 0 by completing the square.

a. x = –5 + √17, x = –5 √–17

b. x = –5 + √21, x = –5 –√21

c. x = 5 + √21, x = 5 –√21

d. x = 5 + √17, x = 5 –√17