7d^2+3d-1=0

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Solution for 7d^2+3d-1=0 equation:


Simplifying
7d2 + 3d + -1 = 0

Reorder the terms:
-1 + 3d + 7d2 = 0

Solving
-1 + 3d + 7d2 = 0

Solving for variable 'd'.

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

Divide each side by '7'.
-0.1428571429 + 0.4285714286d + d2 = 0

Move the constant term to the right:

Add '0.1428571429' to each side of the equation.
-0.1428571429 + 0.4285714286d + 0.1428571429 + d2 = 0 + 0.1428571429

Reorder the terms:
-0.1428571429 + 0.1428571429 + 0.4285714286d + d2 = 0 + 0.1428571429

Combine like terms: -0.1428571429 + 0.1428571429 = 0.0000000000
0.0000000000 + 0.4285714286d + d2 = 0 + 0.1428571429
0.4285714286d + d2 = 0 + 0.1428571429

Combine like terms: 0 + 0.1428571429 = 0.1428571429
0.4285714286d + d2 = 0.1428571429

The d term is 0.4285714286d.  Take half its coefficient (0.2142857143).
Square it (0.04591836735) and add it to both sides.

Add '0.04591836735' to each side of the equation.
0.4285714286d + 0.04591836735 + d2 = 0.1428571429 + 0.04591836735

Reorder the terms:
0.04591836735 + 0.4285714286d + d2 = 0.1428571429 + 0.04591836735

Combine like terms: 0.1428571429 + 0.04591836735 = 0.18877551025
0.04591836735 + 0.4285714286d + d2 = 0.18877551025

Factor a perfect square on the left side:
(d + 0.2142857143)(d + 0.2142857143) = 0.18877551025

Calculate the square root of the right side: 0.434483038

Break this problem into two subproblems by setting 
(d + 0.2142857143) equal to 0.434483038 and -0.434483038.

Subproblem 1

d + 0.2142857143 = 0.434483038 Simplifying d + 0.2142857143 = 0.434483038 Reorder the terms: 0.2142857143 + d = 0.434483038 Solving 0.2142857143 + d = 0.434483038 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '-0.2142857143' to each side of the equation. 0.2142857143 + -0.2142857143 + d = 0.434483038 + -0.2142857143 Combine like terms: 0.2142857143 + -0.2142857143 = 0.0000000000 0.0000000000 + d = 0.434483038 + -0.2142857143 d = 0.434483038 + -0.2142857143 Combine like terms: 0.434483038 + -0.2142857143 = 0.2201973237 d = 0.2201973237 Simplifying d = 0.2201973237

Subproblem 2

d + 0.2142857143 = -0.434483038 Simplifying d + 0.2142857143 = -0.434483038 Reorder the terms: 0.2142857143 + d = -0.434483038 Solving 0.2142857143 + d = -0.434483038 Solving for variable 'd'. Move all terms containing d to the left, all other terms to the right. Add '-0.2142857143' to each side of the equation. 0.2142857143 + -0.2142857143 + d = -0.434483038 + -0.2142857143 Combine like terms: 0.2142857143 + -0.2142857143 = 0.0000000000 0.0000000000 + d = -0.434483038 + -0.2142857143 d = -0.434483038 + -0.2142857143 Combine like terms: -0.434483038 + -0.2142857143 = -0.6487687523 d = -0.6487687523 Simplifying d = -0.6487687523

Solution

The solution to the problem is based on the solutions from the subproblems. d = {0.2201973237, -0.6487687523}

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