15z^4-11z^2+2=0

Solution for 15z^4-11z^2+2=0 equation:

Simplifying
15z4 + -11z2 + 2 = 0

Reorder the terms:
2 + -11z2 + 15z4 = 0

Solving
2 + -11z2 + 15z4 = 0

Solving for variable 'z'.

Factor a trinomial.
(1 + -3z2)(2 + -5z2) = 0

Subproblem 1
Set the factor '(1 + -3z2)' equal to zero and attempt to solve:

Simplifying
1 + -3z2 = 0

Solving
1 + -3z2 = 0

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

Add '-1' to each side of the equation.
1 + -1 + -3z2 = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -3z2 = 0 + -1
-3z2 = 0 + -1

Combine like terms: 0 + -1 = -1
-3z2 = -1

Divide each side by '-3'.
z2 = 0.3333333333

Simplifying
z2 = 0.3333333333

Take the square root of each side:
z = {-0.577350269, 0.577350269}
Subproblem 2
Set the factor '(2 + -5z2)' equal to zero and attempt to solve:

Simplifying
2 + -5z2 = 0

Solving
2 + -5z2 = 0

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

Add '-2' to each side of the equation.
2 + -2 + -5z2 = 0 + -2

Combine like terms: 2 + -2 = 0
0 + -5z2 = 0 + -2
-5z2 = 0 + -2

Combine like terms: 0 + -2 = -2
-5z2 = -2

Divide each side by '-5'.
z2 = 0.4

Simplifying
z2 = 0.4

Take the square root of each side:
z = {-0.632455532, 0.632455532}
Solution
z = {-0.577350269, 0.577350269, -0.632455532, 0.632455532}