y^4-7y^2-144=0

Solution for y^4-7y^2-144=0 equation:

Simplifying
y4 + -7y2 + -144 = 0

Reorder the terms:
-144 + -7y2 + y4 = 0

Solving
-144 + -7y2 + y4 = 0

Solving for variable 'y'.

Factor a trinomial.
(-9 + -1y2)(16 + -1y2) = 0

Factor a difference between two squares.
(-9 + -1y2)((4 + y)(4 + -1y)) = 0

Subproblem 1
Set the factor '(-9 + -1y2)' equal to zero and attempt to solve:

Simplifying
-9 + -1y2 = 0

Solving
-9 + -1y2 = 0

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

Add '9' to each side of the equation.
-9 + 9 + -1y2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + -1y2 = 0 + 9
-1y2 = 0 + 9

Combine like terms: 0 + 9 = 9
-1y2 = 9

Divide each side by '-1'.
y2 = -9

Simplifying
y2 = -9

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 '(4 + y)' equal to zero and attempt to solve:

Simplifying
4 + y = 0

Solving
4 + y = 0

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

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

Combine like terms: 4 + -4 = 0
0 + y = 0 + -4
y = 0 + -4

Combine like terms: 0 + -4 = -4
y = -4

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

Simplifying
4 + -1y = 0

Solving
4 + -1y = 0

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

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

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

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

Divide each side by '-1'.
y = 4

Simplifying
y = 4
Solution
y = {-4, 4}