(r-2t)(r+2t)=

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

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

Multiply (r + -2t) * (r + 2t)
(r(r + 2t) + -2t * (r + 2t)) = 0
((r * r + 2t * r) + -2t * (r + 2t)) = 0

Reorder the terms:
((2rt + r2) + -2t * (r + 2t)) = 0
((2rt + r2) + -2t * (r + 2t)) = 0
(2rt + r2 + (r * -2t + 2t * -2t)) = 0
(2rt + r2 + (-2rt + -4t2)) = 0

Reorder the terms:
(2rt + -2rt + r2 + -4t2) = 0

Combine like terms: 2rt + -2rt = 0
(0 + r2 + -4t2) = 0
(r2 + -4t2) = 0

Solving
r2 + -4t2 = 0

Solving for variable 'r'.

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

Add '4t2' to each side of the equation.
r2 + -4t2 + 4t2 = 0 + 4t2

Combine like terms: -4t2 + 4t2 = 0
r2 + 0 = 0 + 4t2
r2 = 0 + 4t2
Remove the zero:
r2 = 4t2

Simplifying
r2 = 4t2

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