c^2-81c+81=0

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Solution for c^2-81c+81=0 equation:


Simplifying
c2 + -81c + 81 = 0

Reorder the terms:
81 + -81c + c2 = 0

Solving
81 + -81c + c2 = 0

Solving for variable 'c'.

Begin completing the square.

Move the constant term to the right:

Add '-81' to each side of the equation.
81 + -81c + -81 + c2 = 0 + -81

Reorder the terms:
81 + -81 + -81c + c2 = 0 + -81

Combine like terms: 81 + -81 = 0
0 + -81c + c2 = 0 + -81
-81c + c2 = 0 + -81

Combine like terms: 0 + -81 = -81
-81c + c2 = -81

The c term is -81c.  Take half its coefficient (-40.5).
Square it (1640.25) and add it to both sides.

Add '1640.25' to each side of the equation.
-81c + 1640.25 + c2 = -81 + 1640.25

Reorder the terms:
1640.25 + -81c + c2 = -81 + 1640.25

Combine like terms: -81 + 1640.25 = 1559.25
1640.25 + -81c + c2 = 1559.25

Factor a perfect square on the left side:
(c + -40.5)(c + -40.5) = 1559.25

Calculate the square root of the right side: 39.487339743

Break this problem into two subproblems by setting 
(c + -40.5) equal to 39.487339743 and -39.487339743.

Subproblem 1

c + -40.5 = 39.487339743 Simplifying c + -40.5 = 39.487339743 Reorder the terms: -40.5 + c = 39.487339743 Solving -40.5 + c = 39.487339743 Solving for variable 'c'. Move all terms containing c to the left, all other terms to the right. Add '40.5' to each side of the equation. -40.5 + 40.5 + c = 39.487339743 + 40.5 Combine like terms: -40.5 + 40.5 = 0.0 0.0 + c = 39.487339743 + 40.5 c = 39.487339743 + 40.5 Combine like terms: 39.487339743 + 40.5 = 79.987339743 c = 79.987339743 Simplifying c = 79.987339743

Subproblem 2

c + -40.5 = -39.487339743 Simplifying c + -40.5 = -39.487339743 Reorder the terms: -40.5 + c = -39.487339743 Solving -40.5 + c = -39.487339743 Solving for variable 'c'. Move all terms containing c to the left, all other terms to the right. Add '40.5' to each side of the equation. -40.5 + 40.5 + c = -39.487339743 + 40.5 Combine like terms: -40.5 + 40.5 = 0.0 0.0 + c = -39.487339743 + 40.5 c = -39.487339743 + 40.5 Combine like terms: -39.487339743 + 40.5 = 1.012660257 c = 1.012660257 Simplifying c = 1.012660257

Solution

The solution to the problem is based on the solutions from the subproblems. c = {79.987339743, 1.012660257}

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