(4k+9)(4k-9)=

Solution for (4k+9)(4k-9)= equation:

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

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

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

Multiply (9 + 4k) * (-9 + 4k)
(9(-9 + 4k) + 4k * (-9 + 4k)) = 0
((-9 * 9 + 4k * 9) + 4k * (-9 + 4k)) = 0
((-81 + 36k) + 4k * (-9 + 4k)) = 0
(-81 + 36k + (-9 * 4k + 4k * 4k)) = 0
(-81 + 36k + (-36k + 16k2)) = 0

Combine like terms: 36k + -36k = 0
(-81 + 0 + 16k2) = 0
(-81 + 16k2) = 0

Solving
-81 + 16k2 = 0

Solving for variable 'k'.

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

Add '81' to each side of the equation.
-81 + 81 + 16k2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 16k2 = 0 + 81
16k2 = 0 + 81

Combine like terms: 0 + 81 = 81
16k2 = 81

Divide each side by '16'.
k2 = 5.0625

Simplifying
k2 = 5.0625

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