(a-5)(a+5)=100

Solution for (a-5)(a+5)=100 equation:

Simplifying
(a + -5)(a + 5) = 100

Reorder the terms:
(-5 + a)(a + 5) = 100

Reorder the terms:
(-5 + a)(5 + a) = 100

Multiply (-5 + a) * (5 + a)
(-5(5 + a) + a(5 + a)) = 100
((5 * -5 + a * -5) + a(5 + a)) = 100
((-25 + -5a) + a(5 + a)) = 100
(-25 + -5a + (5 * a + a * a)) = 100
(-25 + -5a + (5a + a2)) = 100

Combine like terms: -5a + 5a = 0
(-25 + 0 + a2) = 100
(-25 + a2) = 100

Solving
-25 + a2 = 100

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 + a2 = 100 + 25

Combine like terms: -25 + 25 = 0
0 + a2 = 100 + 25
a2 = 100 + 25

Combine like terms: 100 + 25 = 125
a2 = 125

Simplifying
a2 = 125

Take the square root of each side:
a = {-11.180339887, 11.180339887}