3u^2+5u-28=0

Solution for 3u^2+5u-28=0 equation:

Simplifying
3u2 + 5u + -28 = 0

Reorder the terms:
-28 + 5u + 3u2 = 0

Solving
-28 + 5u + 3u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(-4 + -1u)(7 + -3u) = 0

Subproblem 1
Set the factor '(-4 + -1u)' equal to zero and attempt to solve:

Simplifying
-4 + -1u = 0

Solving
-4 + -1u = 0

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

Add '4' to each side of the equation.
-4 + 4 + -1u = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -1u = 0 + 4
-1u = 0 + 4

Combine like terms: 0 + 4 = 4
-1u = 4

Divide each side by '-1'.
u = -4

Simplifying
u = -4
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 = {-4, 2.333333333}