(4d-9)(4d+9)=0

Solution for (4d-9)(4d+9)=0 equation:

Simplifying
(4d + -9)(4d + 9) = 0

Reorder the terms:
(-9 + 4d)(4d + 9) = 0

Reorder the terms:
(-9 + 4d)(9 + 4d) = 0

Multiply (-9 + 4d) * (9 + 4d)
(-9(9 + 4d) + 4d * (9 + 4d)) = 0
((9 * -9 + 4d * -9) + 4d * (9 + 4d)) = 0
((-81 + -36d) + 4d * (9 + 4d)) = 0
(-81 + -36d + (9 * 4d + 4d * 4d)) = 0
(-81 + -36d + (36d + 16d2)) = 0

Combine like terms: -36d + 36d = 0
(-81 + 0 + 16d2) = 0
(-81 + 16d2) = 0

Solving
-81 + 16d2 = 0

Solving for variable 'd'.

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

Add '81' to each side of the equation.
-81 + 81 + 16d2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 16d2 = 0 + 81
16d2 = 0 + 81

Combine like terms: 0 + 81 = 81
16d2 = 81

Divide each side by '16'.
d2 = 5.0625

Simplifying
d2 = 5.0625

Take the square root of each side:
d = {-2.25, 2.25}