15u^2-13u-20=0

Solution for 15u^2-13u-20=0 equation:

Simplifying
15u2 + -13u + -20 = 0

Reorder the terms:
-20 + -13u + 15u2 = 0

Solving
-20 + -13u + 15u2 = 0

Solving for variable 'u'.

Factor a trinomial.
(-4 + -5u)(5 + -3u) = 0

Subproblem 1
Set the factor '(-4 + -5u)' equal to zero and attempt to solve:

Simplifying
-4 + -5u = 0

Solving
-4 + -5u = 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 + -5u = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -5u = 0 + 4
-5u = 0 + 4

Combine like terms: 0 + 4 = 4
-5u = 4

Divide each side by '-5'.
u = -0.8

Simplifying
u = -0.8
Subproblem 2
Set the factor '(5 + -3u)' equal to zero and attempt to solve:

Simplifying
5 + -3u = 0

Solving
5 + -3u = 0

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

Add '-5' to each side of the equation.
5 + -5 + -3u = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -3u = 0 + -5
-3u = 0 + -5

Combine like terms: 0 + -5 = -5
-3u = -5

Divide each side by '-3'.
u = 1.666666667

Simplifying
u = 1.666666667
Solution
u = {-0.8, 1.666666667}