x*x+18x=-70

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Solution for x*x+18x=-70 equation:


Simplifying
x * x + 18x = -70

Multiply x * x
x2 + 18x = -70

Reorder the terms:
18x + x2 = -70

Solving
18x + x2 = -70

Solving for variable 'x'.

Reorder the terms:
70 + 18x + x2 = -70 + 70

Combine like terms: -70 + 70 = 0
70 + 18x + x2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-70' to each side of the equation.
70 + 18x + -70 + x2 = 0 + -70

Reorder the terms:
70 + -70 + 18x + x2 = 0 + -70

Combine like terms: 70 + -70 = 0
0 + 18x + x2 = 0 + -70
18x + x2 = 0 + -70

Combine like terms: 0 + -70 = -70
18x + x2 = -70

The x term is 18x.  Take half its coefficient (9).
Square it (81) and add it to both sides.

Add '81' to each side of the equation.
18x + 81 + x2 = -70 + 81

Reorder the terms:
81 + 18x + x2 = -70 + 81

Combine like terms: -70 + 81 = 11
81 + 18x + x2 = 11

Factor a perfect square on the left side:
(x + 9)(x + 9) = 11

Calculate the square root of the right side: 3.31662479

Break this problem into two subproblems by setting 
(x + 9) equal to 3.31662479 and -3.31662479.

Subproblem 1

x + 9 = 3.31662479 Simplifying x + 9 = 3.31662479 Reorder the terms: 9 + x = 3.31662479 Solving 9 + x = 3.31662479 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + x = 3.31662479 + -9 Combine like terms: 9 + -9 = 0 0 + x = 3.31662479 + -9 x = 3.31662479 + -9 Combine like terms: 3.31662479 + -9 = -5.68337521 x = -5.68337521 Simplifying x = -5.68337521

Subproblem 2

x + 9 = -3.31662479 Simplifying x + 9 = -3.31662479 Reorder the terms: 9 + x = -3.31662479 Solving 9 + x = -3.31662479 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-9' to each side of the equation. 9 + -9 + x = -3.31662479 + -9 Combine like terms: 9 + -9 = 0 0 + x = -3.31662479 + -9 x = -3.31662479 + -9 Combine like terms: -3.31662479 + -9 = -12.31662479 x = -12.31662479 Simplifying x = -12.31662479

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-5.68337521, -12.31662479}

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