(5c+4)(5c-4)=0

Solution for (5c+4)(5c-4)=0 equation:

Simplifying
(5c + 4)(5c + -4) = 0

Reorder the terms:
(4 + 5c)(5c + -4) = 0

Reorder the terms:
(4 + 5c)(-4 + 5c) = 0

Multiply (4 + 5c) * (-4 + 5c)
(4(-4 + 5c) + 5c * (-4 + 5c)) = 0
((-4 * 4 + 5c * 4) + 5c * (-4 + 5c)) = 0
((-16 + 20c) + 5c * (-4 + 5c)) = 0
(-16 + 20c + (-4 * 5c + 5c * 5c)) = 0
(-16 + 20c + (-20c + 25c2)) = 0

Combine like terms: 20c + -20c = 0
(-16 + 0 + 25c2) = 0
(-16 + 25c2) = 0

Solving
-16 + 25c2 = 0

Solving for variable 'c'.

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

Add '16' to each side of the equation.
-16 + 16 + 25c2 = 0 + 16

Combine like terms: -16 + 16 = 0
0 + 25c2 = 0 + 16
25c2 = 0 + 16

Combine like terms: 0 + 16 = 16
25c2 = 16

Divide each side by '25'.
c2 = 0.64

Simplifying
c2 = 0.64

Take the square root of each side:
c = {-0.8, 0.8}