(3r+8)(3r-8)=

Solution for (3r+8)(3r-8)= equation:

Simplifying
(3r + 8)(3r + -8) = 0

Reorder the terms:
(8 + 3r)(3r + -8) = 0

Reorder the terms:
(8 + 3r)(-8 + 3r) = 0

Multiply (8 + 3r) * (-8 + 3r)
(8(-8 + 3r) + 3r * (-8 + 3r)) = 0
((-8 * 8 + 3r * 8) + 3r * (-8 + 3r)) = 0
((-64 + 24r) + 3r * (-8 + 3r)) = 0
(-64 + 24r + (-8 * 3r + 3r * 3r)) = 0
(-64 + 24r + (-24r + 9r2)) = 0

Combine like terms: 24r + -24r = 0
(-64 + 0 + 9r2) = 0
(-64 + 9r2) = 0

Solving
-64 + 9r2 = 0

Solving for variable 'r'.

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

Add '64' to each side of the equation.
-64 + 64 + 9r2 = 0 + 64

Combine like terms: -64 + 64 = 0
0 + 9r2 = 0 + 64
9r2 = 0 + 64

Combine like terms: 0 + 64 = 64
9r2 = 64

Divide each side by '9'.
r2 = 7.111111111

Simplifying
r2 = 7.111111111

Take the square root of each side:
r = {-2.666666667, 2.666666667}