81-25y^4=0

Solution for 81-25y^4=0 equation:

Simplifying
81 + -25y4 = 0

Solving
81 + -25y4 = 0

Solving for variable 'y'.

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

Add '-81' to each side of the equation.
81 + -81 + -25y4 = 0 + -81

Combine like terms: 81 + -81 = 0
0 + -25y4 = 0 + -81
-25y4 = 0 + -81

Combine like terms: 0 + -81 = -81
-25y4 = -81

Divide each side by '-25'.
y4 = 3.24

Simplifying
y4 = 3.24

Reorder the terms:
-3.24 + y4 = 3.24 + -3.24

Combine like terms: 3.24 + -3.24 = 0.00
-3.24 + y4 = 0.00

Factor a difference between two squares.
(1.8 + y2)(-1.8 + y2) = 0.00

Subproblem 1
Set the factor '(1.8 + y2)' equal to zero and attempt to solve:

Simplifying
1.8 + y2 = 0

Solving
1.8 + y2 = 0

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

Add '-1.8' to each side of the equation.
1.8 + -1.8 + y2 = 0 + -1.8

Combine like terms: 1.8 + -1.8 = 0.0
0.0 + y2 = 0 + -1.8
y2 = 0 + -1.8

Combine like terms: 0 + -1.8 = -1.8
y2 = -1.8

Simplifying
y2 = -1.8

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.
Subproblem 2
Set the factor '(-1.8 + y2)' equal to zero and attempt to solve:

Simplifying
-1.8 + y2 = 0

Solving
-1.8 + y2 = 0

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

Add '1.8' to each side of the equation.
-1.8 + 1.8 + y2 = 0 + 1.8

Combine like terms: -1.8 + 1.8 = 0.0
0.0 + y2 = 0 + 1.8
y2 = 0 + 1.8

Combine like terms: 0 + 1.8 = 1.8
y2 = 1.8

Simplifying
y2 = 1.8

Take the square root of each side:
y = {-1.341640787, 1.341640787}
Solution
y = {-1.341640787, 1.341640787}