r^2-28r+36=0

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Solution for r^2-28r+36=0 equation:


Simplifying
r2 + -28r + 36 = 0

Reorder the terms:
36 + -28r + r2 = 0

Solving
36 + -28r + r2 = 0

Solving for variable 'r'.

Begin completing the square.

Move the constant term to the right:

Add '-36' to each side of the equation.
36 + -28r + -36 + r2 = 0 + -36

Reorder the terms:
36 + -36 + -28r + r2 = 0 + -36

Combine like terms: 36 + -36 = 0
0 + -28r + r2 = 0 + -36
-28r + r2 = 0 + -36

Combine like terms: 0 + -36 = -36
-28r + r2 = -36

The r term is -28r.  Take half its coefficient (-14).
Square it (196) and add it to both sides.

Add '196' to each side of the equation.
-28r + 196 + r2 = -36 + 196

Reorder the terms:
196 + -28r + r2 = -36 + 196

Combine like terms: -36 + 196 = 160
196 + -28r + r2 = 160

Factor a perfect square on the left side:
(r + -14)(r + -14) = 160

Calculate the square root of the right side: 12.649110641

Break this problem into two subproblems by setting 
(r + -14) equal to 12.649110641 and -12.649110641.

Subproblem 1

r + -14 = 12.649110641 Simplifying r + -14 = 12.649110641 Reorder the terms: -14 + r = 12.649110641 Solving -14 + r = 12.649110641 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '14' to each side of the equation. -14 + 14 + r = 12.649110641 + 14 Combine like terms: -14 + 14 = 0 0 + r = 12.649110641 + 14 r = 12.649110641 + 14 Combine like terms: 12.649110641 + 14 = 26.649110641 r = 26.649110641 Simplifying r = 26.649110641

Subproblem 2

r + -14 = -12.649110641 Simplifying r + -14 = -12.649110641 Reorder the terms: -14 + r = -12.649110641 Solving -14 + r = -12.649110641 Solving for variable 'r'. Move all terms containing r to the left, all other terms to the right. Add '14' to each side of the equation. -14 + 14 + r = -12.649110641 + 14 Combine like terms: -14 + 14 = 0 0 + r = -12.649110641 + 14 r = -12.649110641 + 14 Combine like terms: -12.649110641 + 14 = 1.350889359 r = 1.350889359 Simplifying r = 1.350889359

Solution

The solution to the problem is based on the solutions from the subproblems. r = {26.649110641, 1.350889359}

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