How do you solve x 2-18x-4 equals 0 by completing the square?

x² - 18x - 4 = o

x² - 18x = 4

x² - 18x + (18/2)² = 4 + (18/2)²

x² - 18x + 81 = 4 + 81

(x - 9)² = 85

x - 9 = ±√85

x = 9 ±√85

x = 9 + √85 or x = 9 - √85

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