Question

Solve the equation x^2 + 5x = -1 by completing the square.

Answer 1

According to the equation,

x² + 5x = - 1

x² + 5x + 1 = 0

Using Quadric Formula

x = - b ± √ b² - 4ac / 2a

x = - (5) ± √ (5)² - 4 (1) (1) / 2 (1)

x = - 5 ± √ 25 -4 / 2

x = - 5 ± √ 21 / 2

So the required answer is

- 5 ± √ 21

x = —————

2

The answer is option C or 3.