To solve the equation x^2 + 4x - 11 = 0 by completing the square, we can follow these steps:
Move the constant term to the right side of the equation:
x^2 + 4x = 11
Complete the square by adding the square of half the coefficient of x to both sides of the equation:
x^2 + 4x + (4/2)^2 = 11 + (4/2)^2
Simplifying the left side:
x^2 + 4x + 4 = 11 + 4
Factor the perfect square on the left side of the equation:
(x + 2)^2 = 15
Take the square root of both sides of the equation:
x + 2 = ±√15
Solve for x by subtracting 2 from both sides:
x = -2 ± √15
Therefore, the solutions to the equation x^2 + 4x - 11 = 0 by completing the square are x = -2 + √15 and x = -2 - √15.