(3+u)(3-u)=

Solution for (3+u)(3-u)= equation:

Simplifying
(3 + u)(3 + -1u) = 0

Multiply (3 + u) * (3 + -1u)
(3(3 + -1u) + u(3 + -1u)) = 0
((3 * 3 + -1u * 3) + u(3 + -1u)) = 0
((9 + -3u) + u(3 + -1u)) = 0
(9 + -3u + (3 * u + -1u * u)) = 0
(9 + -3u + (3u + -1u2)) = 0

Combine like terms: -3u + 3u = 0
(9 + 0 + -1u2) = 0
(9 + -1u2) = 0

Solving
9 + -1u2 = 0

Solving for variable 'u'.

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

Add '-9' to each side of the equation.
9 + -9 + -1u2 = 0 + -9

Combine like terms: 9 + -9 = 0
0 + -1u2 = 0 + -9
-1u2 = 0 + -9

Combine like terms: 0 + -9 = -9
-1u2 = -9

Divide each side by '-1'.
u2 = 9

Simplifying
u2 = 9

Take the square root of each side:
u = {-3, 3}