y^2-90y+1800=0

Solution for y^2-90y+1800=0 equation:

Simplifying
y2 + -90y + 1800 = 0

Reorder the terms:
1800 + -90y + y2 = 0

Solving
1800 + -90y + y2 = 0

Solving for variable 'y'.

Factor a trinomial.
(30 + -1y)(60 + -1y) = 0

Subproblem 1
Set the factor '(30 + -1y)' equal to zero and attempt to solve:

Simplifying
30 + -1y = 0

Solving
30 + -1y = 0

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

Add '-30' to each side of the equation.
30 + -30 + -1y = 0 + -30

Combine like terms: 30 + -30 = 0
0 + -1y = 0 + -30
-1y = 0 + -30

Combine like terms: 0 + -30 = -30
-1y = -30

Divide each side by '-1'.
y = 30

Simplifying
y = 30
Subproblem 2
Set the factor '(60 + -1y)' equal to zero and attempt to solve:

Simplifying
60 + -1y = 0

Solving
60 + -1y = 0

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

Add '-60' to each side of the equation.
60 + -60 + -1y = 0 + -60

Combine like terms: 60 + -60 = 0
0 + -1y = 0 + -60
-1y = 0 + -60

Combine like terms: 0 + -60 = -60
-1y = -60

Divide each side by '-1'.
y = 60

Simplifying
y = 60
Solution
y = {30, 60}