(4b+5)(4b-5)=0

Solution for (4b+5)(4b-5)=0 equation:

Simplifying
(4b + 5)(4b + -5) = 0

Reorder the terms:
(5 + 4b)(4b + -5) = 0

Reorder the terms:
(5 + 4b)(-5 + 4b) = 0

Multiply (5 + 4b) * (-5 + 4b)
(5(-5 + 4b) + 4b * (-5 + 4b)) = 0
((-5 * 5 + 4b * 5) + 4b * (-5 + 4b)) = 0
((-25 + 20b) + 4b * (-5 + 4b)) = 0
(-25 + 20b + (-5 * 4b + 4b * 4b)) = 0
(-25 + 20b + (-20b + 16b2)) = 0

Combine like terms: 20b + -20b = 0
(-25 + 0 + 16b2) = 0
(-25 + 16b2) = 0

Solving
-25 + 16b2 = 0

Solving for variable 'b'.

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

Add '25' to each side of the equation.
-25 + 25 + 16b2 = 0 + 25

Combine like terms: -25 + 25 = 0
0 + 16b2 = 0 + 25
16b2 = 0 + 25

Combine like terms: 0 + 25 = 25
16b2 = 25

Divide each side by '16'.
b2 = 1.5625

Simplifying
b2 = 1.5625

Take the square root of each side:
b = {-1.25, 1.25}