(2y-9)(2y+9)=

Solution for (2y-9)(2y+9)= equation:

Simplifying
(2y + -9)(2y + 9) = 0

Reorder the terms:
(-9 + 2y)(2y + 9) = 0

Reorder the terms:
(-9 + 2y)(9 + 2y) = 0

Multiply (-9 + 2y) * (9 + 2y)
(-9(9 + 2y) + 2y * (9 + 2y)) = 0
((9 * -9 + 2y * -9) + 2y * (9 + 2y)) = 0
((-81 + -18y) + 2y * (9 + 2y)) = 0
(-81 + -18y + (9 * 2y + 2y * 2y)) = 0
(-81 + -18y + (18y + 4y2)) = 0

Combine like terms: -18y + 18y = 0
(-81 + 0 + 4y2) = 0
(-81 + 4y2) = 0

Solving
-81 + 4y2 = 0

Solving for variable 'y'.

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

Add '81' to each side of the equation.
-81 + 81 + 4y2 = 0 + 81

Combine like terms: -81 + 81 = 0
0 + 4y2 = 0 + 81
4y2 = 0 + 81

Combine like terms: 0 + 81 = 81
4y2 = 81

Divide each side by '4'.
y2 = 20.25

Simplifying
y2 = 20.25

Take the square root of each side:
y = {-4.5, 4.5}