x^2-7x-18=03

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Solution for x^2-7x-18=03 equation:


Simplifying
x2 + -7x + -18 = 3

Reorder the terms:
-18 + -7x + x2 = 3

Solving
-18 + -7x + x2 = 3

Solving for variable 'x'.

Reorder the terms:
-18 + -3 + -7x + x2 = 3 + -3

Combine like terms: -18 + -3 = -21
-21 + -7x + x2 = 3 + -3

Combine like terms: 3 + -3 = 0
-21 + -7x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '21' to each side of the equation.
-21 + -7x + 21 + x2 = 0 + 21

Reorder the terms:
-21 + 21 + -7x + x2 = 0 + 21

Combine like terms: -21 + 21 = 0
0 + -7x + x2 = 0 + 21
-7x + x2 = 0 + 21

Combine like terms: 0 + 21 = 21
-7x + x2 = 21

The x term is -7x.  Take half its coefficient (-3.5).
Square it (12.25) and add it to both sides.

Add '12.25' to each side of the equation.
-7x + 12.25 + x2 = 21 + 12.25

Reorder the terms:
12.25 + -7x + x2 = 21 + 12.25

Combine like terms: 21 + 12.25 = 33.25
12.25 + -7x + x2 = 33.25

Factor a perfect square on the left side:
(x + -3.5)(x + -3.5) = 33.25

Calculate the square root of the right side: 5.766281297

Break this problem into two subproblems by setting 
(x + -3.5) equal to 5.766281297 and -5.766281297.

Subproblem 1

x + -3.5 = 5.766281297 Simplifying x + -3.5 = 5.766281297 Reorder the terms: -3.5 + x = 5.766281297 Solving -3.5 + x = 5.766281297 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '3.5' to each side of the equation. -3.5 + 3.5 + x = 5.766281297 + 3.5 Combine like terms: -3.5 + 3.5 = 0.0 0.0 + x = 5.766281297 + 3.5 x = 5.766281297 + 3.5 Combine like terms: 5.766281297 + 3.5 = 9.266281297 x = 9.266281297 Simplifying x = 9.266281297

Subproblem 2

x + -3.5 = -5.766281297 Simplifying x + -3.5 = -5.766281297 Reorder the terms: -3.5 + x = -5.766281297 Solving -3.5 + x = -5.766281297 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '3.5' to each side of the equation. -3.5 + 3.5 + x = -5.766281297 + 3.5 Combine like terms: -3.5 + 3.5 = 0.0 0.0 + x = -5.766281297 + 3.5 x = -5.766281297 + 3.5 Combine like terms: -5.766281297 + 3.5 = -2.266281297 x = -2.266281297 Simplifying x = -2.266281297

Solution

The solution to the problem is based on the solutions from the subproblems. x = {9.266281297, -2.266281297}

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