(5x+9)(5x-9)=36

Solution for (5x+9)(5x-9)=36 equation:

Simplifying
(5x + 9)(5x + -9) = 36

Reorder the terms:
(9 + 5x)(5x + -9) = 36

Reorder the terms:
(9 + 5x)(-9 + 5x) = 36

Multiply (9 + 5x) * (-9 + 5x)
(9(-9 + 5x) + 5x * (-9 + 5x)) = 36
((-9 * 9 + 5x * 9) + 5x * (-9 + 5x)) = 36
((-81 + 45x) + 5x * (-9 + 5x)) = 36
(-81 + 45x + (-9 * 5x + 5x * 5x)) = 36
(-81 + 45x + (-45x + 25x2)) = 36

Combine like terms: 45x + -45x = 0
(-81 + 0 + 25x2) = 36
(-81 + 25x2) = 36

Solving
-81 + 25x2 = 36

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 + 25x2 = 36 + 81

Combine like terms: -81 + 81 = 0
0 + 25x2 = 36 + 81
25x2 = 36 + 81

Combine like terms: 36 + 81 = 117
25x2 = 117

Divide each side by '25'.
x2 = 4.68

Simplifying
x2 = 4.68

Take the square root of each side:
x = {-2.163330765, 2.163330765}