(2r+4)(2r-4)=

Solution for (2r+4)(2r-4)= equation:

Simplifying
(2r + 4)(2r + -4) = 0

Reorder the terms:
(4 + 2r)(2r + -4) = 0

Reorder the terms:
(4 + 2r)(-4 + 2r) = 0

Multiply (4 + 2r) * (-4 + 2r)
(4(-4 + 2r) + 2r * (-4 + 2r)) = 0
((-4 * 4 + 2r * 4) + 2r * (-4 + 2r)) = 0
((-16 + 8r) + 2r * (-4 + 2r)) = 0
(-16 + 8r + (-4 * 2r + 2r * 2r)) = 0
(-16 + 8r + (-8r + 4r2)) = 0

Combine like terms: 8r + -8r = 0
(-16 + 0 + 4r2) = 0
(-16 + 4r2) = 0

Solving
-16 + 4r2 = 0

Solving for variable 'r'.

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

Add '16' to each side of the equation.
-16 + 16 + 4r2 = 0 + 16

Combine like terms: -16 + 16 = 0
0 + 4r2 = 0 + 16
4r2 = 0 + 16

Combine like terms: 0 + 16 = 16
4r2 = 16

Divide each side by '4'.
r2 = 4

Simplifying
r2 = 4

Take the square root of each side:
r = {-2, 2}