7n^2+5n-8=0

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Solution for 7n^2+5n-8=0 equation:


Simplifying
7n2 + 5n + -8 = 0

Reorder the terms:
-8 + 5n + 7n2 = 0

Solving
-8 + 5n + 7n2 = 0

Solving for variable 'n'.

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

Divide each side by '7'.
-1.142857143 + 0.7142857143n + n2 = 0

Move the constant term to the right:

Add '1.142857143' to each side of the equation.
-1.142857143 + 0.7142857143n + 1.142857143 + n2 = 0 + 1.142857143

Reorder the terms:
-1.142857143 + 1.142857143 + 0.7142857143n + n2 = 0 + 1.142857143

Combine like terms: -1.142857143 + 1.142857143 = 0.000000000
0.000000000 + 0.7142857143n + n2 = 0 + 1.142857143
0.7142857143n + n2 = 0 + 1.142857143

Combine like terms: 0 + 1.142857143 = 1.142857143
0.7142857143n + n2 = 1.142857143

The n term is 0.7142857143n.  Take half its coefficient (0.3571428572).
Square it (0.1275510204) and add it to both sides.

Add '0.1275510204' to each side of the equation.
0.7142857143n + 0.1275510204 + n2 = 1.142857143 + 0.1275510204

Reorder the terms:
0.1275510204 + 0.7142857143n + n2 = 1.142857143 + 0.1275510204

Combine like terms: 1.142857143 + 0.1275510204 = 1.2704081634
0.1275510204 + 0.7142857143n + n2 = 1.2704081634

Factor a perfect square on the left side:
(n + 0.3571428572)(n + 0.3571428572) = 1.2704081634

Calculate the square root of the right side: 1.127123846

Break this problem into two subproblems by setting 
(n + 0.3571428572) equal to 1.127123846 and -1.127123846.

Subproblem 1

n + 0.3571428572 = 1.127123846 Simplifying n + 0.3571428572 = 1.127123846 Reorder the terms: 0.3571428572 + n = 1.127123846 Solving 0.3571428572 + n = 1.127123846 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '-0.3571428572' to each side of the equation. 0.3571428572 + -0.3571428572 + n = 1.127123846 + -0.3571428572 Combine like terms: 0.3571428572 + -0.3571428572 = 0.0000000000 0.0000000000 + n = 1.127123846 + -0.3571428572 n = 1.127123846 + -0.3571428572 Combine like terms: 1.127123846 + -0.3571428572 = 0.7699809888 n = 0.7699809888 Simplifying n = 0.7699809888

Subproblem 2

n + 0.3571428572 = -1.127123846 Simplifying n + 0.3571428572 = -1.127123846 Reorder the terms: 0.3571428572 + n = -1.127123846 Solving 0.3571428572 + n = -1.127123846 Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '-0.3571428572' to each side of the equation. 0.3571428572 + -0.3571428572 + n = -1.127123846 + -0.3571428572 Combine like terms: 0.3571428572 + -0.3571428572 = 0.0000000000 0.0000000000 + n = -1.127123846 + -0.3571428572 n = -1.127123846 + -0.3571428572 Combine like terms: -1.127123846 + -0.3571428572 = -1.4842667032 n = -1.4842667032 Simplifying n = -1.4842667032

Solution

The solution to the problem is based on the solutions from the subproblems. n = {0.7699809888, -1.4842667032}

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