Hello from MrBillDoesMath!
Answer:
x = -1 +\- sqrt(5)
Discussion:
Generally, to "complete the square", add (1/2) the coefficient of x, that is (1/2)(-2) = -1, squared, to both sides of the equation:
x^2 -2x + (-1)^2 - (-1)^2 -4 = 0 => simplify using (-1)^2 = 1
(x^2 - 2x + 1) -1 -4 = 0 => add 5 to both sides
(x^2 - 2x + 1) = 5 =>
(x+1)^2 = 5 => take square root of both sides
x+1 = +\-sqrt(5) => subtract 1 from both sides
x = -1 +\- sqrt(5)
Thank you,
MrB
