(s-9)(s+9)=

Solution for (s-9)(s+9)= equation:

Simplifying
(s + -9)(s + 9) = 0

Reorder the terms:
(-9 + s)(s + 9) = 0

Reorder the terms:
(-9 + s)(9 + s) = 0

Multiply (-9 + s) * (9 + s)
(-9(9 + s) + s(9 + s)) = 0
((9 * -9 + s * -9) + s(9 + s)) = 0
((-81 + -9s) + s(9 + s)) = 0
(-81 + -9s + (9 * s + s * s)) = 0
(-81 + -9s + (9s + s2)) = 0

Combine like terms: -9s + 9s = 0
(-81 + 0 + s2) = 0
(-81 + s2) = 0

Solving
-81 + s2 = 0

Solving for variable 's'.

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

Add '81' to each side of the equation.
-81 + 81 + s2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + s2 = 0 + 81
s2 = 0 + 81

Combine like terms: 0 + 81 = 81
s2 = 81

Simplifying
s2 = 81

Take the square root of each side:
s = {-9, 9}