r^2-12r+5=0

Solution for r^2-12r+5=0 equation:

Simplifying
r2 + -12r + 5 = 0

Reorder the terms:
5 + -12r + r2 = 0

Solving
5 + -12r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-5' to each side of the equation.
5 + -12r + -5 + r2 = 0 + -5

Reorder the terms:
5 + -5 + -12r + r2 = 0 + -5

Combine like terms: 5 + -5 = 0
0 + -12r + r2 = 0 + -5
-12r + r2 = 0 + -5

Combine like terms: 0 + -5 = -5
-12r + r2 = -5

The r term is -12r.  Take half its coefficient (-6).
Square it (36) and add it to both sides.

Add '36' to each side of the equation.
-12r + 36 + r2 = -5 + 36

Reorder the terms:
36 + -12r + r2 = -5 + 36

Combine like terms: -5 + 36 = 31
36 + -12r + r2 = 31

Factor a perfect square on the left side:
(r + -6)(r + -6) = 31

Calculate the square root of the right side: 5.567764363

Break this problem into two subproblems by setting 
(r + -6) equal to 5.567764363 and -5.567764363.

Subproblem 1
r + -6 = 5.567764363

Simplifying
r + -6 = 5.567764363

Reorder the terms:
-6 + r = 5.567764363

Solving
-6 + r = 5.567764363

Solving for variable 'r'.

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

Add '6' to each side of the equation.
-6 + 6 + r = 5.567764363 + 6

Combine like terms: -6 + 6 = 0
0 + r = 5.567764363 + 6
r = 5.567764363 + 6

Combine like terms: 5.567764363 + 6 = 11.567764363
r = 11.567764363

Simplifying
r = 11.567764363

Subproblem 2
r + -6 = -5.567764363

Simplifying
r + -6 = -5.567764363

Reorder the terms:
-6 + r = -5.567764363

Solving
-6 + r = -5.567764363

Solving for variable 'r'.

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

Add '6' to each side of the equation.
-6 + 6 + r = -5.567764363 + 6

Combine like terms: -6 + 6 = 0
0 + r = -5.567764363 + 6
r = -5.567764363 + 6

Combine like terms: -5.567764363 + 6 = 0.432235637
r = 0.432235637

Simplifying
r = 0.432235637

Solution
The solution to the problem is based on the solutions
from the subproblems.
r = {11.567764363, 0.432235637}