(h-9)(h+9)=0

Solution for (h-9)(h+9)=0 equation:

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

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

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

Multiply (-9 + h) * (9 + h)
(-9(9 + h) + h(9 + h)) = 0
((9 * -9 + h * -9) + h(9 + h)) = 0
((-81 + -9h) + h(9 + h)) = 0
(-81 + -9h + (9 * h + h * h)) = 0
(-81 + -9h + (9h + h2)) = 0

Combine like terms: -9h + 9h = 0
(-81 + 0 + h2) = 0
(-81 + h2) = 0

Solving
-81 + h2 = 0

Solving for variable 'h'.

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

Add '81' to each side of the equation.
-81 + 81 + h2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + h2 = 0 + 81
h2 = 0 + 81

Combine like terms: 0 + 81 = 81
h2 = 81

Simplifying
h2 = 81

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