Question

Solve x^(2)+4x=4 for x by completing the square.

Answer 1

x = 2 sqrt(2) - 2 or x = -2 - 2 sqrt(2)

Explanation:

Solve for x:

x^2 + 4 x = 4

Add 4 to both sides:

x^2 + 4 x + 4 = 8

Write the left hand side as a square:

(x + 2)^2 = 8

Take the square root of both sides:

x + 2 = 2 sqrt(2) or x + 2 = -2 sqrt(2)

Subtract 2 from both sides:

x = 2 sqrt(2) - 2 or x + 2 = -2 sqrt(2)

Subtract 2 from both sides:

Answer: x = 2 sqrt(2) - 2 or x = -2 - 2 sqrt(2)