(3+u)(2u-7)=0

Solution for (3+u)(2u-7)=0 equation:

Simplifying
(3 + u)(2u + -7) = 0

Reorder the terms:
(3 + u)(-7 + 2u) = 0

Multiply (3 + u) * (-7 + 2u)
(3(-7 + 2u) + u(-7 + 2u)) = 0
((-7 * 3 + 2u * 3) + u(-7 + 2u)) = 0
((-21 + 6u) + u(-7 + 2u)) = 0
(-21 + 6u + (-7 * u + 2u * u)) = 0
(-21 + 6u + (-7u + 2u2)) = 0

Combine like terms: 6u + -7u = -1u
(-21 + -1u + 2u2) = 0

Solving
-21 + -1u + 2u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(-3 + -1u)(7 + -2u) = 0

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

Simplifying
-3 + -1u = 0

Solving
-3 + -1u = 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 + -1u = 0 + 3

Combine like terms: -3 + 3 = 0
0 + -1u = 0 + 3
-1u = 0 + 3

Combine like terms: 0 + 3 = 3
-1u = 3

Divide each side by '-1'.
u = -3

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

Simplifying
7 + -2u = 0

Solving
7 + -2u = 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 + -2u = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -2u = 0 + -7
-2u = 0 + -7

Combine like terms: 0 + -7 = -7
-2u = -7

Divide each side by '-2'.
u = 3.5

Simplifying
u = 3.5
Solution
u = {-3, 3.5}