z^4=9z^2

Solution for z^4=9z^2 equation:

Simplifying
z4 = 9z2

Solving
z4 = 9z2

Solving for variable 'z'.

Reorder the terms:
-9z2 + z4 = 9z2 + -9z2

Combine like terms: 9z2 + -9z2 = 0
-9z2 + z4 = 0

Factor out the Greatest Common Factor (GCF), 'z2'.
z2(-9 + z2) = 0

Factor a difference between two squares.
z2((3 + z)(-3 + z)) = 0

Subproblem 1
Set the factor 'z2' equal to zero and attempt to solve:

Simplifying
z2 = 0

Solving
z2 = 0

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

Simplifying
z2 = 0

Take the square root of each side:
z = {0}
Subproblem 2
Set the factor '(3 + z)' equal to zero and attempt to solve:

Simplifying
3 + z = 0

Solving
3 + z = 0

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

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

Combine like terms: 3 + -3 = 0
0 + z = 0 + -3
z = 0 + -3

Combine like terms: 0 + -3 = -3
z = -3

Simplifying
z = -3
Subproblem 3
Set the factor '(-3 + z)' equal to zero and attempt to solve:

Simplifying
-3 + z = 0

Solving
-3 + z = 0

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

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

Combine like terms: -3 + 3 = 0
0 + z = 0 + 3
z = 0 + 3

Combine like terms: 0 + 3 = 3
z = 3

Simplifying
z = 3
Solution
z = {0, -3, 3}