Solve x^2+8x-5 = 0 by completing the square.

x² + 8x = (x + 4)² - 16, so x² + 8x - 5 = (x + 4)² - 16 - 5 = (x + 4)² - 21, so then (x + 4)² - 21 = 0 (x + 4)² = 21 -----> x + 4 = √21 -------> x = -4 + √21                               x = -4 - √21