7x^2+9x=-1

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Solution for 7x^2+9x=-1 equation:


Simplifying
7x2 + 9x = -1

Reorder the terms:
9x + 7x2 = -1

Solving
9x + 7x2 = -1

Solving for variable 'x'.

Reorder the terms:
1 + 9x + 7x2 = -1 + 1

Combine like terms: -1 + 1 = 0
1 + 9x + 7x2 = 0

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

Divide each side by '7'.
0.1428571429 + 1.285714286x + x2 = 0

Move the constant term to the right:

Add '-0.1428571429' to each side of the equation.
0.1428571429 + 1.285714286x + -0.1428571429 + x2 = 0 + -0.1428571429

Reorder the terms:
0.1428571429 + -0.1428571429 + 1.285714286x + x2 = 0 + -0.1428571429

Combine like terms: 0.1428571429 + -0.1428571429 = 0.0000000000
0.0000000000 + 1.285714286x + x2 = 0 + -0.1428571429
1.285714286x + x2 = 0 + -0.1428571429

Combine like terms: 0 + -0.1428571429 = -0.1428571429
1.285714286x + x2 = -0.1428571429

The x term is 1.285714286x.  Take half its coefficient (0.642857143).
Square it (0.4132653063) and add it to both sides.

Add '0.4132653063' to each side of the equation.
1.285714286x + 0.4132653063 + x2 = -0.1428571429 + 0.4132653063

Reorder the terms:
0.4132653063 + 1.285714286x + x2 = -0.1428571429 + 0.4132653063

Combine like terms: -0.1428571429 + 0.4132653063 = 0.2704081634
0.4132653063 + 1.285714286x + x2 = 0.2704081634

Factor a perfect square on the left side:
(x + 0.642857143)(x + 0.642857143) = 0.2704081634

Calculate the square root of the right side: 0.520007849

Break this problem into two subproblems by setting 
(x + 0.642857143) equal to 0.520007849 and -0.520007849.

Subproblem 1

x + 0.642857143 = 0.520007849 Simplifying x + 0.642857143 = 0.520007849 Reorder the terms: 0.642857143 + x = 0.520007849 Solving 0.642857143 + x = 0.520007849 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.642857143' to each side of the equation. 0.642857143 + -0.642857143 + x = 0.520007849 + -0.642857143 Combine like terms: 0.642857143 + -0.642857143 = 0.000000000 0.000000000 + x = 0.520007849 + -0.642857143 x = 0.520007849 + -0.642857143 Combine like terms: 0.520007849 + -0.642857143 = -0.122849294 x = -0.122849294 Simplifying x = -0.122849294

Subproblem 2

x + 0.642857143 = -0.520007849 Simplifying x + 0.642857143 = -0.520007849 Reorder the terms: 0.642857143 + x = -0.520007849 Solving 0.642857143 + x = -0.520007849 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-0.642857143' to each side of the equation. 0.642857143 + -0.642857143 + x = -0.520007849 + -0.642857143 Combine like terms: 0.642857143 + -0.642857143 = 0.000000000 0.000000000 + x = -0.520007849 + -0.642857143 x = -0.520007849 + -0.642857143 Combine like terms: -0.520007849 + -0.642857143 = -1.162864992 x = -1.162864992 Simplifying x = -1.162864992

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.122849294, -1.162864992}

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