(x+3y)(x-3y)=

Solution for (x+3y)(x-3y)= equation:

Simplifying
(x + 3y)(x + -3y) = 0

Multiply (x + 3y) * (x + -3y)
(x(x + -3y) + 3y * (x + -3y)) = 0
((x * x + -3y * x) + 3y * (x + -3y)) = 0

Reorder the terms:
((-3xy + x2) + 3y * (x + -3y)) = 0
((-3xy + x2) + 3y * (x + -3y)) = 0
(-3xy + x2 + (x * 3y + -3y * 3y)) = 0
(-3xy + x2 + (3xy + -9y2)) = 0

Reorder the terms:
(-3xy + 3xy + x2 + -9y2) = 0

Combine like terms: -3xy + 3xy = 0
(0 + x2 + -9y2) = 0
(x2 + -9y2) = 0

Solving
x2 + -9y2 = 0

Solving for variable 'x'.

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

Add '9y2' to each side of the equation.
x2 + -9y2 + 9y2 = 0 + 9y2

Combine like terms: -9y2 + 9y2 = 0
x2 + 0 = 0 + 9y2
x2 = 0 + 9y2
Remove the zero:
x2 = 9y2

Simplifying
x2 = 9y2

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