x^2+3x-91=0

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Solution for x^2+3x-91=0 equation:


Simplifying
x2 + 3x + -91 = 0

Reorder the terms:
-91 + 3x + x2 = 0

Solving
-91 + 3x + x2 = 0

Solving for variable 'x'.

Begin completing the square.

Move the constant term to the right:

Add '91' to each side of the equation.
-91 + 3x + 91 + x2 = 0 + 91

Reorder the terms:
-91 + 91 + 3x + x2 = 0 + 91

Combine like terms: -91 + 91 = 0
0 + 3x + x2 = 0 + 91
3x + x2 = 0 + 91

Combine like terms: 0 + 91 = 91
3x + x2 = 91

The x term is 3x.  Take half its coefficient (1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
3x + 2.25 + x2 = 91 + 2.25

Reorder the terms:
2.25 + 3x + x2 = 91 + 2.25

Combine like terms: 91 + 2.25 = 93.25
2.25 + 3x + x2 = 93.25

Factor a perfect square on the left side:
(x + 1.5)(x + 1.5) = 93.25

Calculate the square root of the right side: 9.656603958

Break this problem into two subproblems by setting 
(x + 1.5) equal to 9.656603958 and -9.656603958.

Subproblem 1

x + 1.5 = 9.656603958 Simplifying x + 1.5 = 9.656603958 Reorder the terms: 1.5 + x = 9.656603958 Solving 1.5 + x = 9.656603958 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.5' to each side of the equation. 1.5 + -1.5 + x = 9.656603958 + -1.5 Combine like terms: 1.5 + -1.5 = 0.0 0.0 + x = 9.656603958 + -1.5 x = 9.656603958 + -1.5 Combine like terms: 9.656603958 + -1.5 = 8.156603958 x = 8.156603958 Simplifying x = 8.156603958

Subproblem 2

x + 1.5 = -9.656603958 Simplifying x + 1.5 = -9.656603958 Reorder the terms: 1.5 + x = -9.656603958 Solving 1.5 + x = -9.656603958 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-1.5' to each side of the equation. 1.5 + -1.5 + x = -9.656603958 + -1.5 Combine like terms: 1.5 + -1.5 = 0.0 0.0 + x = -9.656603958 + -1.5 x = -9.656603958 + -1.5 Combine like terms: -9.656603958 + -1.5 = -11.156603958 x = -11.156603958 Simplifying x = -11.156603958

Solution

The solution to the problem is based on the solutions from the subproblems. x = {8.156603958, -11.156603958}

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