(2n+9)(2n-9)=

Solution for (2n+9)(2n-9)= equation:

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

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

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

Multiply (9 + 2n) * (-9 + 2n)
(9(-9 + 2n) + 2n * (-9 + 2n)) = 0
((-9 * 9 + 2n * 9) + 2n * (-9 + 2n)) = 0
((-81 + 18n) + 2n * (-9 + 2n)) = 0
(-81 + 18n + (-9 * 2n + 2n * 2n)) = 0
(-81 + 18n + (-18n + 4n2)) = 0

Combine like terms: 18n + -18n = 0
(-81 + 0 + 4n2) = 0
(-81 + 4n2) = 0

Solving
-81 + 4n2 = 0

Solving for variable 'n'.

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

Add '81' to each side of the equation.
-81 + 81 + 4n2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 4n2 = 0 + 81
4n2 = 0 + 81

Combine like terms: 0 + 81 = 81
4n2 = 81

Divide each side by '4'.
n2 = 20.25

Simplifying
n2 = 20.25

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