-x^2-4x=-47

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Solution for -x^2-4x=-47 equation:


Simplifying
-1x2 + -4x = -47

Reorder the terms:
-4x + -1x2 = -47

Solving
-4x + -1x2 = -47

Solving for variable 'x'.

Reorder the terms:
47 + -4x + -1x2 = -47 + 47

Combine like terms: -47 + 47 = 0
47 + -4x + -1x2 = 0

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
-47 + 4x + x2 = 0

Move the constant term to the right:

Add '47' to each side of the equation.
-47 + 4x + 47 + x2 = 0 + 47

Reorder the terms:
-47 + 47 + 4x + x2 = 0 + 47

Combine like terms: -47 + 47 = 0
0 + 4x + x2 = 0 + 47
4x + x2 = 0 + 47

Combine like terms: 0 + 47 = 47
4x + x2 = 47

The x term is 4x.  Take half its coefficient (2).
Square it (4) and add it to both sides.

Add '4' to each side of the equation.
4x + 4 + x2 = 47 + 4

Reorder the terms:
4 + 4x + x2 = 47 + 4

Combine like terms: 47 + 4 = 51
4 + 4x + x2 = 51

Factor a perfect square on the left side:
(x + 2)(x + 2) = 51

Calculate the square root of the right side: 7.141428429

Break this problem into two subproblems by setting 
(x + 2) equal to 7.141428429 and -7.141428429.

Subproblem 1

x + 2 = 7.141428429 Simplifying x + 2 = 7.141428429 Reorder the terms: 2 + x = 7.141428429 Solving 2 + x = 7.141428429 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-2' to each side of the equation. 2 + -2 + x = 7.141428429 + -2 Combine like terms: 2 + -2 = 0 0 + x = 7.141428429 + -2 x = 7.141428429 + -2 Combine like terms: 7.141428429 + -2 = 5.141428429 x = 5.141428429 Simplifying x = 5.141428429

Subproblem 2

x + 2 = -7.141428429 Simplifying x + 2 = -7.141428429 Reorder the terms: 2 + x = -7.141428429 Solving 2 + x = -7.141428429 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-2' to each side of the equation. 2 + -2 + x = -7.141428429 + -2 Combine like terms: 2 + -2 = 0 0 + x = -7.141428429 + -2 x = -7.141428429 + -2 Combine like terms: -7.141428429 + -2 = -9.141428429 x = -9.141428429 Simplifying x = -9.141428429

Solution

The solution to the problem is based on the solutions from the subproblems. x = {5.141428429, -9.141428429}

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