(3u+7)(3+u)=

Solution for (3u+7)(3+u)= equation:

Simplifying
(3u + 7)(3 + u) = 0

Reorder the terms:
(7 + 3u)(3 + u) = 0

Multiply (7 + 3u) * (3 + u)
(7(3 + u) + 3u * (3 + u)) = 0
((3 * 7 + u * 7) + 3u * (3 + u)) = 0
((21 + 7u) + 3u * (3 + u)) = 0
(21 + 7u + (3 * 3u + u * 3u)) = 0
(21 + 7u + (9u + 3u2)) = 0

Combine like terms: 7u + 9u = 16u
(21 + 16u + 3u2) = 0

Solving
21 + 16u + 3u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(3 + u)(7 + 3u) = 0

Subproblem 1
Set the factor '(3 + u)' equal to zero and attempt to solve:

Simplifying
3 + u = 0

Solving
3 + u = 0

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

Add '-3' to each side of the equation.
3 + -3 + u = 0 + -3

Combine like terms: 3 + -3 = 0
0 + u = 0 + -3
u = 0 + -3

Combine like terms: 0 + -3 = -3
u = -3

Simplifying
u = -3
Subproblem 2
Set the factor '(7 + 3u)' equal to zero and attempt to solve:

Simplifying
7 + 3u = 0

Solving
7 + 3u = 0

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

Add '-7' to each side of the equation.
7 + -7 + 3u = 0 + -7

Combine like terms: 7 + -7 = 0
0 + 3u = 0 + -7
3u = 0 + -7

Combine like terms: 0 + -7 = -7
3u = -7

Divide each side by '3'.
u = -2.333333333

Simplifying
u = -2.333333333
Solution
u = {-3, -2.333333333}