x^2+3x-1=0 by completing the square
x^2+3x-1=0
x^2 + 3x = 1
Add (1/2 * 3)^2. That's 1.5^2, which is 2.25
x^2 + 3x + 2.25 = 1 + 2.25 = 3.25
Factor the left side.
(x + 1.5)(x + 1.5) = 3.25
Take the square root of both sides.
x + 1.5 = 1.80277
x = 1.80277 - 1.5
x = 0.30277