y(5y-4)+(81+y^2)=0

Solution for y(5y-4)+(81+y^2)=0 equation:

Simplifying
y(5y + -4) + (81 + y2) = 0

Reorder the terms:
y(-4 + 5y) + (81 + y2) = 0
(-4 * y + 5y * y) + (81 + y2) = 0
(-4y + 5y2) + (81 + y2) = 0

Remove parenthesis around (81 + y2)
-4y + 5y2 + 81 + y2 = 0

Reorder the terms:
81 + -4y + 5y2 + y2 = 0

Combine like terms: 5y2 + y2 = 6y2
81 + -4y + 6y2 = 0

Solving
81 + -4y + 6y2 = 0

Solving for variable 'y'.

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

Divide each side by '6'.
13.5 + -0.6666666667y + y2 = 0

Move the constant term to the right:

Add '-13.5' to each side of the equation.
13.5 + -0.6666666667y + -13.5 + y2 = 0 + -13.5

Reorder the terms:
13.5 + -13.5 + -0.6666666667y + y2 = 0 + -13.5

Combine like terms: 13.5 + -13.5 = 0.0
0.0 + -0.6666666667y + y2 = 0 + -13.5
-0.6666666667y + y2 = 0 + -13.5

Combine like terms: 0 + -13.5 = -13.5
-0.6666666667y + y2 = -13.5

The y term is -0.6666666667y.  Take half its coefficient (-0.3333333334).
Square it (0.1111111112) and add it to both sides.

Add '0.1111111112' to each side of the equation.
-0.6666666667y + 0.1111111112 + y2 = -13.5 + 0.1111111112

Reorder the terms:
0.1111111112 + -0.6666666667y + y2 = -13.5 + 0.1111111112

Combine like terms: -13.5 + 0.1111111112 = -13.3888888888
0.1111111112 + -0.6666666667y + y2 = -13.3888888888

Factor a perfect square on the left side:
(y + -0.3333333334)(y + -0.3333333334) = -13.3888888888

Can't calculate square root of the right side.

The solution to this equation could not be determined.