(3x-4)(3x+4)=65

Solution for (3x-4)(3x+4)=65 equation:

Simplifying
(3x + -4)(3x + 4) = 65

Reorder the terms:
(-4 + 3x)(3x + 4) = 65

Reorder the terms:
(-4 + 3x)(4 + 3x) = 65

Multiply (-4 + 3x) * (4 + 3x)
(-4(4 + 3x) + 3x * (4 + 3x)) = 65
((4 * -4 + 3x * -4) + 3x * (4 + 3x)) = 65
((-16 + -12x) + 3x * (4 + 3x)) = 65
(-16 + -12x + (4 * 3x + 3x * 3x)) = 65
(-16 + -12x + (12x + 9x2)) = 65

Combine like terms: -12x + 12x = 0
(-16 + 0 + 9x2) = 65
(-16 + 9x2) = 65

Solving
-16 + 9x2 = 65

Solving for variable 'x'.

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

Add '16' to each side of the equation.
-16 + 16 + 9x2 = 65 + 16

Combine like terms: -16 + 16 = 0
0 + 9x2 = 65 + 16
9x2 = 65 + 16

Combine like terms: 65 + 16 = 81
9x2 = 81

Divide each side by '9'.
x2 = 9

Simplifying
x2 = 9

Take the square root of each side:
x = {-3, 3}