3u^2+u-1=0

Solution for 3u^2+u-1=0 equation:

Simplifying
3u2 + u + -1 = 0

Reorder the terms:
-1 + u + 3u2 = 0

Solving
-1 + u + 3u2 = 0

Solving for variable 'u'.

Begin completing the square.  Divide all terms by
3 the coefficient of the squared term: 

Divide each side by '3'.
-0.3333333333 + 0.3333333333u + u2 = 0

Move the constant term to the right:

Add '0.3333333333' to each side of the equation.
-0.3333333333 + 0.3333333333u + 0.3333333333 + u2 = 0 + 0.3333333333

Reorder the terms:
-0.3333333333 + 0.3333333333 + 0.3333333333u + u2 = 0 + 0.3333333333

Combine like terms: -0.3333333333 + 0.3333333333 = 0.0000000000
0.0000000000 + 0.3333333333u + u2 = 0 + 0.3333333333
0.3333333333u + u2 = 0 + 0.3333333333

Combine like terms: 0 + 0.3333333333 = 0.3333333333
0.3333333333u + u2 = 0.3333333333

The u term is u.  Take half its coefficient (0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
0.3333333333u + 0.25 + u2 = 0.3333333333 + 0.25

Reorder the terms:
0.25 + 0.3333333333u + u2 = 0.3333333333 + 0.25

Combine like terms: 0.3333333333 + 0.25 = 0.5833333333
0.25 + 0.3333333333u + u2 = 0.5833333333

Factor a perfect square on the left side:
(u + 0.5)(u + 0.5) = 0.5833333333

Calculate the square root of the right side: 0.763762616

Break this problem into two subproblems by setting 
(u + 0.5) equal to 0.763762616 and -0.763762616.

Subproblem 1
u + 0.5 = 0.763762616

Simplifying
u + 0.5 = 0.763762616

Reorder the terms:
0.5 + u = 0.763762616

Solving
0.5 + u = 0.763762616

Solving for variable 'u'.

Move all terms containing u to the left, all other terms to the right.

Add '-0.5' to each side of the equation.
0.5 + -0.5 + u = 0.763762616 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + u = 0.763762616 + -0.5
u = 0.763762616 + -0.5

Combine like terms: 0.763762616 + -0.5 = 0.263762616
u = 0.263762616

Simplifying
u = 0.263762616

Subproblem 2
u + 0.5 = -0.763762616

Simplifying
u + 0.5 = -0.763762616

Reorder the terms:
0.5 + u = -0.763762616

Solving
0.5 + u = -0.763762616

Solving for variable 'u'.

Move all terms containing u to the left, all other terms to the right.

Add '-0.5' to each side of the equation.
0.5 + -0.5 + u = -0.763762616 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + u = -0.763762616 + -0.5
u = -0.763762616 + -0.5

Combine like terms: -0.763762616 + -0.5 = -1.263762616
u = -1.263762616

Simplifying
u = -1.263762616

Solution
The solution to the problem is based on the solutions
from the subproblems.
u = {0.263762616, -1.263762616}