(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}