x*x+4*x=7

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Solution for x*x+4*x=7 equation:


Simplifying
x * x + 4x = 7

Multiply x * x
x2 + 4x = 7

Reorder the terms:
4x + x2 = 7

Solving
4x + x2 = 7

Solving for variable 'x'.

Reorder the terms:
-7 + 4x + x2 = 7 + -7

Combine like terms: 7 + -7 = 0
-7 + 4x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '7' to each side of the equation.
-7 + 4x + 7 + x2 = 0 + 7

Reorder the terms:
-7 + 7 + 4x + x2 = 0 + 7

Combine like terms: -7 + 7 = 0
0 + 4x + x2 = 0 + 7
4x + x2 = 0 + 7

Combine like terms: 0 + 7 = 7
4x + x2 = 7

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 = 7 + 4

Reorder the terms:
4 + 4x + x2 = 7 + 4

Combine like terms: 7 + 4 = 11
4 + 4x + x2 = 11

Factor a perfect square on the left side:
(x + 2)(x + 2) = 11

Calculate the square root of the right side: 3.31662479

Break this problem into two subproblems by setting 
(x + 2) equal to 3.31662479 and -3.31662479.

Subproblem 1

x + 2 = 3.31662479 Simplifying x + 2 = 3.31662479 Reorder the terms: 2 + x = 3.31662479 Solving 2 + x = 3.31662479 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 = 3.31662479 + -2 Combine like terms: 2 + -2 = 0 0 + x = 3.31662479 + -2 x = 3.31662479 + -2 Combine like terms: 3.31662479 + -2 = 1.31662479 x = 1.31662479 Simplifying x = 1.31662479

Subproblem 2

x + 2 = -3.31662479 Simplifying x + 2 = -3.31662479 Reorder the terms: 2 + x = -3.31662479 Solving 2 + x = -3.31662479 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 = -3.31662479 + -2 Combine like terms: 2 + -2 = 0 0 + x = -3.31662479 + -2 x = -3.31662479 + -2 Combine like terms: -3.31662479 + -2 = -5.31662479 x = -5.31662479 Simplifying x = -5.31662479

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.31662479, -5.31662479}

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