(5b-9)(5b+9)=

Solution for (5b-9)(5b+9)= equation:

Simplifying
(5b + -9)(5b + 9) = 0

Reorder the terms:
(-9 + 5b)(5b + 9) = 0

Reorder the terms:
(-9 + 5b)(9 + 5b) = 0

Multiply (-9 + 5b) * (9 + 5b)
(-9(9 + 5b) + 5b * (9 + 5b)) = 0
((9 * -9 + 5b * -9) + 5b * (9 + 5b)) = 0
((-81 + -45b) + 5b * (9 + 5b)) = 0
(-81 + -45b + (9 * 5b + 5b * 5b)) = 0
(-81 + -45b + (45b + 25b2)) = 0

Combine like terms: -45b + 45b = 0
(-81 + 0 + 25b2) = 0
(-81 + 25b2) = 0

Solving
-81 + 25b2 = 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 + 25b2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 25b2 = 0 + 81
25b2 = 0 + 81

Combine like terms: 0 + 81 = 81
25b2 = 81

Divide each side by '25'.
b2 = 3.24

Simplifying
b2 = 3.24

Take the square root of each side:
b = {-1.8, 1.8}