(x^2-9b)(x^2+9b)=0

Solution for (x^2-9b)(x^2+9b)=0 equation:

Simplifying
(x2 + -9b)(x2 + 9b) = 0

Reorder the terms:
(-9b + x2)(x2 + 9b) = 0

Reorder the terms:
(-9b + x2)(9b + x2) = 0

Multiply (-9b + x2) * (9b + x2)
(-9b * (9b + x2) + x2(9b + x2)) = 0
((9b * -9b + x2 * -9b) + x2(9b + x2)) = 0

Reorder the terms:
((-9bx2 + -81b2) + x2(9b + x2)) = 0
((-9bx2 + -81b2) + x2(9b + x2)) = 0
(-9bx2 + -81b2 + (9b * x2 + x2 * x2)) = 0
(-9bx2 + -81b2 + (9bx2 + x4)) = 0

Reorder the terms:
(-9bx2 + 9bx2 + -81b2 + x4) = 0

Combine like terms: -9bx2 + 9bx2 = 0
(0 + -81b2 + x4) = 0
(-81b2 + x4) = 0

Solving
-81b2 + x4 = 0

Solving for variable 'b'.

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

Add '-1x4' to each side of the equation.
-81b2 + x4 + -1x4 = 0 + -1x4

Combine like terms: x4 + -1x4 = 0
-81b2 + 0 = 0 + -1x4
-81b2 = 0 + -1x4
Remove the zero:
-81b2 = -1x4

Divide each side by '-81'.
b2 = 0.01234567901x4

Simplifying
b2 = 0.01234567901x4

Take the square root of each side:
b = {-0.111111111x2, 0.111111111x2}