(b-9)(b+9)=

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

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

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

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

Multiply (-9 + b) * (9 + b)
(-9(9 + b) + b(9 + b)) = 0
((9 * -9 + b * -9) + b(9 + b)) = 0
((-81 + -9b) + b(9 + b)) = 0
(-81 + -9b + (9 * b + b * b)) = 0
(-81 + -9b + (9b + b2)) = 0

Combine like terms: -9b + 9b = 0
(-81 + 0 + b2) = 0
(-81 + b2) = 0

Solving
-81 + b2 = 0

Solving for variable 'b'.

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

Add '81' to each side of the equation.
-81 + 81 + b2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + b2 = 0 + 81
b2 = 0 + 81

Combine like terms: 0 + 81 = 81
b2 = 81

Simplifying
b2 = 81

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