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

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

Simplifying
(-2x + 9)(-2x + -9) = 0

Reorder the terms:
(9 + -2x)(-2x + -9) = 0

Reorder the terms:
(9 + -2x)(-9 + -2x) = 0

Multiply (9 + -2x) * (-9 + -2x)
(9(-9 + -2x) + -2x * (-9 + -2x)) = 0
((-9 * 9 + -2x * 9) + -2x * (-9 + -2x)) = 0
((-81 + -18x) + -2x * (-9 + -2x)) = 0
(-81 + -18x + (-9 * -2x + -2x * -2x)) = 0
(-81 + -18x + (18x + 4x2)) = 0

Combine like terms: -18x + 18x = 0
(-81 + 0 + 4x2) = 0
(-81 + 4x2) = 0

Solving
-81 + 4x2 = 0

Solving for variable 'x'.

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

Add '81' to each side of the equation.
-81 + 81 + 4x2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 4x2 = 0 + 81
4x2 = 0 + 81

Combine like terms: 0 + 81 = 81
4x2 = 81

Divide each side by '4'.
x2 = 20.25

Simplifying
x2 = 20.25

Take the square root of each side:
x = {-4.5, 4.5}