-5u^2-20u+225=0

Solution for -5u^2-20u+225=0 equation:

Simplifying
-5u2 + -20u + 225 = 0

Reorder the terms:
225 + -20u + -5u2 = 0

Solving
225 + -20u + -5u2 = 0

Solving for variable 'u'.

Factor out the Greatest Common Factor (GCF), '5'.
5(45 + -4u + -1u2) = 0

Factor a trinomial.
5((5 + -1u)(9 + u)) = 0

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

Simplifying
5 + -1u = 0

Solving
5 + -1u = 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 + -1u = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -1u = 0 + -5
-1u = 0 + -5

Combine like terms: 0 + -5 = -5
-1u = -5

Divide each side by '-1'.
u = 5

Simplifying
u = 5
Subproblem 2
Set the factor '(9 + u)' equal to zero and attempt to solve:

Simplifying
9 + u = 0

Solving
9 + u = 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 + u = 0 + -9

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

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

Simplifying
u = -9
Solution
u = {5, -9}