4n^2-21n-5=10n

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Solution for 4n^2-21n-5=10n equation:


Simplifying
4n2 + -21n + -5 = 10n

Reorder the terms:
-5 + -21n + 4n2 = 10n

Solving
-5 + -21n + 4n2 = 10n

Solving for variable 'n'.

Reorder the terms:
-5 + -21n + -10n + 4n2 = 10n + -10n

Combine like terms: -21n + -10n = -31n
-5 + -31n + 4n2 = 10n + -10n

Combine like terms: 10n + -10n = 0
-5 + -31n + 4n2 = 0

Begin completing the square.  Divide all terms by
4 the coefficient of the squared term: 

Divide each side by '4'.
-1.25 + -7.75n + n2 = 0

Move the constant term to the right:

Add '1.25' to each side of the equation.
-1.25 + -7.75n + 1.25 + n2 = 0 + 1.25

Reorder the terms:
-1.25 + 1.25 + -7.75n + n2 = 0 + 1.25

Combine like terms: -1.25 + 1.25 = 0.00
0.00 + -7.75n + n2 = 0 + 1.25
-7.75n + n2 = 0 + 1.25

Combine like terms: 0 + 1.25 = 1.25
-7.75n + n2 = 1.25

The n term is -7.75n.  Take half its coefficient (-3.875).
Square it (15.015625) and add it to both sides.

Add '15.015625' to each side of the equation.
-7.75n + 15.015625 + n2 = 1.25 + 15.015625

Reorder the terms:
15.015625 + -7.75n + n2 = 1.25 + 15.015625

Combine like terms: 1.25 + 15.015625 = 16.265625
15.015625 + -7.75n + n2 = 16.265625

Factor a perfect square on the left side:
(n + -3.875)(n + -3.875) = 16.265625

Calculate the square root of the right side: 4.033066451

Break this problem into two subproblems by setting 
(n + -3.875) equal to 4.033066451 and -4.033066451.

Subproblem 1

n + -3.875 = 4.033066451 Simplifying n + -3.875 = 4.033066451 Reorder the terms: -3.875 + n = 4.033066451 Solving -3.875 + n = 4.033066451 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '3.875' to each side of the equation. -3.875 + 3.875 + n = 4.033066451 + 3.875 Combine like terms: -3.875 + 3.875 = 0.000 0.000 + n = 4.033066451 + 3.875 n = 4.033066451 + 3.875 Combine like terms: 4.033066451 + 3.875 = 7.908066451 n = 7.908066451 Simplifying n = 7.908066451

Subproblem 2

n + -3.875 = -4.033066451 Simplifying n + -3.875 = -4.033066451 Reorder the terms: -3.875 + n = -4.033066451 Solving -3.875 + n = -4.033066451 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '3.875' to each side of the equation. -3.875 + 3.875 + n = -4.033066451 + 3.875 Combine like terms: -3.875 + 3.875 = 0.000 0.000 + n = -4.033066451 + 3.875 n = -4.033066451 + 3.875 Combine like terms: -4.033066451 + 3.875 = -0.158066451 n = -0.158066451 Simplifying n = -0.158066451

Solution

The solution to the problem is based on the solutions from the subproblems. n = {7.908066451, -0.158066451}

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