(-a-5)(a-5)=0

Solution for (-a-5)(a-5)=0 equation:

Simplifying
(-1a + -5)(a + -5) = 0

Reorder the terms:
(-5 + -1a)(a + -5) = 0

Reorder the terms:
(-5 + -1a)(-5 + a) = 0

Multiply (-5 + -1a) * (-5 + a)
(-5(-5 + a) + -1a * (-5 + a)) = 0
((-5 * -5 + a * -5) + -1a * (-5 + a)) = 0
((25 + -5a) + -1a * (-5 + a)) = 0
(25 + -5a + (-5 * -1a + a * -1a)) = 0
(25 + -5a + (5a + -1a2)) = 0

Combine like terms: -5a + 5a = 0
(25 + 0 + -1a2) = 0
(25 + -1a2) = 0

Solving
25 + -1a2 = 0

Solving for variable 'a'.

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

Add '-25' to each side of the equation.
25 + -25 + -1a2 = 0 + -25

Combine like terms: 25 + -25 = 0
0 + -1a2 = 0 + -25
-1a2 = 0 + -25

Combine like terms: 0 + -25 = -25
-1a2 = -25

Divide each side by '-1'.
a2 = 25

Simplifying
a2 = 25

Take the square root of each side:
a = {-5, 5}