y(y+15)=100

Solution for y(y+15)=100 equation:

Simplifying
y(y + 15) = 100

Reorder the terms:
y(15 + y) = 100
(15 * y + y * y) = 100
(15y + y2) = 100

Solving
15y + y2 = 100

Solving for variable 'y'.

Reorder the terms:
-100 + 15y + y2 = 100 + -100

Combine like terms: 100 + -100 = 0
-100 + 15y + y2 = 0

Factor a trinomial.
(-20 + -1y)(5 + -1y) = 0

Subproblem 1
Set the factor '(-20 + -1y)' equal to zero and attempt to solve:

Simplifying
-20 + -1y = 0

Solving
-20 + -1y = 0

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

Add '20' to each side of the equation.
-20 + 20 + -1y = 0 + 20

Combine like terms: -20 + 20 = 0
0 + -1y = 0 + 20
-1y = 0 + 20

Combine like terms: 0 + 20 = 20
-1y = 20

Divide each side by '-1'.
y = -20

Simplifying
y = -20
Subproblem 2
Set the factor '(5 + -1y)' equal to zero and attempt to solve:

Simplifying
5 + -1y = 0

Solving
5 + -1y = 0

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

Add '-5' to each side of the equation.
5 + -5 + -1y = 0 + -5

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

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

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

Simplifying
y = 5
Solution
y = {-20, 5}