16a^4+15a^2-1=0

Solution for 16a^4+15a^2-1=0 equation:

Simplifying
16a4 + 15a2 + -1 = 0

Reorder the terms:
-1 + 15a2 + 16a4 = 0

Solving
-1 + 15a2 + 16a4 = 0

Solving for variable 'a'.

Factor a trinomial.
(-1 + -1a2)(1 + -16a2) = 0

Factor a difference between two squares.
(-1 + -1a2)((1 + 4a)(1 + -4a)) = 0

Subproblem 1
Set the factor '(-1 + -1a2)' equal to zero and attempt to solve:

Simplifying
-1 + -1a2 = 0

Solving
-1 + -1a2 = 0

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

Add '1' to each side of the equation.
-1 + 1 + -1a2 = 0 + 1

Combine like terms: -1 + 1 = 0
0 + -1a2 = 0 + 1
-1a2 = 0 + 1

Combine like terms: 0 + 1 = 1
-1a2 = 1

Divide each side by '-1'.
a2 = -1

Simplifying
a2 = -1

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 + 4a)' equal to zero and attempt to solve:

Simplifying
1 + 4a = 0

Solving
1 + 4a = 0

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

Add '-1' to each side of the equation.
1 + -1 + 4a = 0 + -1

Combine like terms: 1 + -1 = 0
0 + 4a = 0 + -1
4a = 0 + -1

Combine like terms: 0 + -1 = -1
4a = -1

Divide each side by '4'.
a = -0.25

Simplifying
a = -0.25
Subproblem 3
Set the factor '(1 + -4a)' equal to zero and attempt to solve:

Simplifying
1 + -4a = 0

Solving
1 + -4a = 0

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

Add '-1' to each side of the equation.
1 + -1 + -4a = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -4a = 0 + -1
-4a = 0 + -1

Combine like terms: 0 + -1 = -1
-4a = -1

Divide each side by '-4'.
a = 0.25

Simplifying
a = 0.25
Solution
a = {-0.25, 0.25}