n^2-42n+441=0

Solution for n^2-42n+441=0 equation:

Simplifying
n2 + -42n + 441 = 0

Reorder the terms:
441 + -42n + n2 = 0

Solving
441 + -42n + n2 = 0

Solving for variable 'n'.

Factor a trinomial.
(21 + -1n)(21 + -1n) = 0

Subproblem 1
Set the factor '(21 + -1n)' equal to zero and attempt to solve:

Simplifying
21 + -1n = 0

Solving
21 + -1n = 0

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

Add '-21' to each side of the equation.
21 + -21 + -1n = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -1n = 0 + -21
-1n = 0 + -21

Combine like terms: 0 + -21 = -21
-1n = -21

Divide each side by '-1'.
n = 21

Simplifying
n = 21
Subproblem 2
Set the factor '(21 + -1n)' equal to zero and attempt to solve:

Simplifying
21 + -1n = 0

Solving
21 + -1n = 0

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

Add '-21' to each side of the equation.
21 + -21 + -1n = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -1n = 0 + -21
-1n = 0 + -21

Combine like terms: 0 + -21 = -21
-1n = -21

Divide each side by '-1'.
n = 21

Simplifying
n = 21
Solution
n = {21, 21}