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)- 21 = 0 (x + 4)= 21 -----> x + 4 = √21 -------> x = -4 + √21                               x = -4 - √21

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Answered by Shadab J. Maths tutor

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