3*(y*y)+y=6

Solution for 3*(y*y)+y=6 equation:

Simplifying
3(y * y) + y = 6

Multiply y * y
3(y2) + y = 6

Reorder the terms:
y + 3y2 = 6

Solving
y + 3y2 = 6

Solving for variable 'y'.

Reorder the terms:
-6 + y + 3y2 = 6 + -6

Combine like terms: 6 + -6 = 0
-6 + y + 3y2 = 0

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

Divide each side by '3'.
-2 + 0.3333333333y + y2 = 0

Move the constant term to the right:

Add '2' to each side of the equation.
-2 + 0.3333333333y + 2 + y2 = 0 + 2

Reorder the terms:
-2 + 2 + 0.3333333333y + y2 = 0 + 2

Combine like terms: -2 + 2 = 0
0 + 0.3333333333y + y2 = 0 + 2
0.3333333333y + y2 = 0 + 2

Combine like terms: 0 + 2 = 2
0.3333333333y + y2 = 2

The y term is y.  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.
0.3333333333y + 0.25 + y2 = 2 + 0.25

Reorder the terms:
0.25 + 0.3333333333y + y2 = 2 + 0.25

Combine like terms: 2 + 0.25 = 2.25
0.25 + 0.3333333333y + y2 = 2.25

Factor a perfect square on the left side:
(y + 0.5)(y + 0.5) = 2.25

Calculate the square root of the right side: 1.5

Break this problem into two subproblems by setting 
(y + 0.5) equal to 1.5 and -1.5.

Subproblem 1
y + 0.5 = 1.5

Simplifying
y + 0.5 = 1.5

Reorder the terms:
0.5 + y = 1.5

Solving
0.5 + y = 1.5

Solving for variable 'y'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + y = 1.5 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + y = 1.5 + -0.5
y = 1.5 + -0.5

Combine like terms: 1.5 + -0.5 = 1
y = 1

Simplifying
y = 1

Subproblem 2
y + 0.5 = -1.5

Simplifying
y + 0.5 = -1.5

Reorder the terms:
0.5 + y = -1.5

Solving
0.5 + y = -1.5

Solving for variable 'y'.

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

Add '-0.5' to each side of the equation.
0.5 + -0.5 + y = -1.5 + -0.5

Combine like terms: 0.5 + -0.5 = 0.0
0.0 + y = -1.5 + -0.5
y = -1.5 + -0.5

Combine like terms: -1.5 + -0.5 = -2
y = -2

Simplifying
y = -2

Solution
The solution to the problem is based on the solutions
from the subproblems.
y = {1, -2}