(r+3)(r-3)=0

Solution for (r+3)(r-3)=0 equation:

Simplifying
(r + 3)(r + -3) = 0

Reorder the terms:
(3 + r)(r + -3) = 0

Reorder the terms:
(3 + r)(-3 + r) = 0

Multiply (3 + r) * (-3 + r)
(3(-3 + r) + r(-3 + r)) = 0
((-3 * 3 + r * 3) + r(-3 + r)) = 0
((-9 + 3r) + r(-3 + r)) = 0
(-9 + 3r + (-3 * r + r * r)) = 0
(-9 + 3r + (-3r + r2)) = 0

Combine like terms: 3r + -3r = 0
(-9 + 0 + r2) = 0
(-9 + r2) = 0

Solving
-9 + r2 = 0

Solving for variable 'r'.

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

Add '9' to each side of the equation.
-9 + 9 + r2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + r2 = 0 + 9
r2 = 0 + 9

Combine like terms: 0 + 9 = 9
r2 = 9

Simplifying
r2 = 9

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