0=u^2-u-72

Solution for 0=u^2-u-72 equation:

Simplifying
0 = u2 + -1u + -72

Reorder the terms:
0 = -72 + -1u + u2

Solving
0 = -72 + -1u + u2

Solving for variable 'u'.

Combine like terms: 0 + 72 = 72
72 + u + -1u2 = -72 + -1u + u2 + 72 + u + -1u2

Reorder the terms:
72 + u + -1u2 = -72 + 72 + -1u + u + u2 + -1u2

Combine like terms: -72 + 72 = 0
72 + u + -1u2 = 0 + -1u + u + u2 + -1u2
72 + u + -1u2 = -1u + u + u2 + -1u2

Combine like terms: -1u + u = 0
72 + u + -1u2 = 0 + u2 + -1u2
72 + u + -1u2 = u2 + -1u2

Combine like terms: u2 + -1u2 = 0
72 + u + -1u2 = 0

Factor a trinomial.
(9 + -1u)(8 + u) = 0

Subproblem 1
Set the factor '(9 + -1u)' equal to zero and attempt to solve:

Simplifying
9 + -1u = 0

Solving
9 + -1u = 0

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

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

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

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

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

Simplifying
u = 9
Subproblem 2
Set the factor '(8 + u)' equal to zero and attempt to solve:

Simplifying
8 + u = 0

Solving
8 + u = 0

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

Add '-8' to each side of the equation.
8 + -8 + u = 0 + -8

Combine like terms: 8 + -8 = 0
0 + u = 0 + -8
u = 0 + -8

Combine like terms: 0 + -8 = -8
u = -8

Simplifying
u = -8
Solution
u = {9, -8}