(c+2d)(c-2d)=0

Solution for (c+2d)(c-2d)=0 equation:

Simplifying
(c + 2d)(c + -2d) = 0

Multiply (c + 2d) * (c + -2d)
(c(c + -2d) + 2d * (c + -2d)) = 0
((c * c + -2d * c) + 2d * (c + -2d)) = 0

Reorder the terms:
((-2cd + c2) + 2d * (c + -2d)) = 0
((-2cd + c2) + 2d * (c + -2d)) = 0
(-2cd + c2 + (c * 2d + -2d * 2d)) = 0
(-2cd + c2 + (2cd + -4d2)) = 0

Reorder the terms:
(-2cd + 2cd + c2 + -4d2) = 0

Combine like terms: -2cd + 2cd = 0
(0 + c2 + -4d2) = 0
(c2 + -4d2) = 0

Solving
c2 + -4d2 = 0

Solving for variable 'c'.

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

Add '4d2' to each side of the equation.
c2 + -4d2 + 4d2 = 0 + 4d2

Combine like terms: -4d2 + 4d2 = 0
c2 + 0 = 0 + 4d2
c2 = 0 + 4d2
Remove the zero:
c2 = 4d2

Simplifying
c2 = 4d2

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