(3r+5)(3r-5)=0

Solution for (3r+5)(3r-5)=0 equation:

Simplifying
(3r + 5)(3r + -5) = 0

Reorder the terms:
(5 + 3r)(3r + -5) = 0

Reorder the terms:
(5 + 3r)(-5 + 3r) = 0

Multiply (5 + 3r) * (-5 + 3r)
(5(-5 + 3r) + 3r * (-5 + 3r)) = 0
((-5 * 5 + 3r * 5) + 3r * (-5 + 3r)) = 0
((-25 + 15r) + 3r * (-5 + 3r)) = 0
(-25 + 15r + (-5 * 3r + 3r * 3r)) = 0
(-25 + 15r + (-15r + 9r2)) = 0

Combine like terms: 15r + -15r = 0
(-25 + 0 + 9r2) = 0
(-25 + 9r2) = 0

Solving
-25 + 9r2 = 0

Solving for variable 'r'.

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

Add '25' to each side of the equation.
-25 + 25 + 9r2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + 9r2 = 0 + 25
9r2 = 0 + 25

Combine like terms: 0 + 25 = 25
9r2 = 25

Divide each side by '9'.
r2 = 2.777777778

Simplifying
r2 = 2.777777778

Take the square root of each side:
r = {-1.666666667, 1.666666667}