3x^2=-21x-15

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Solution for 3x^2=-21x-15 equation:


Simplifying
3x2 = -21x + -15

Reorder the terms:
3x2 = -15 + -21x

Solving
3x2 = -15 + -21x

Solving for variable 'x'.

Reorder the terms:
15 + 21x + 3x2 = -15 + -21x + 15 + 21x

Reorder the terms:
15 + 21x + 3x2 = -15 + 15 + -21x + 21x

Combine like terms: -15 + 15 = 0
15 + 21x + 3x2 = 0 + -21x + 21x
15 + 21x + 3x2 = -21x + 21x

Combine like terms: -21x + 21x = 0
15 + 21x + 3x2 = 0

Factor out the Greatest Common Factor (GCF), '3'.
3(5 + 7x + x2) = 0

Ignore the factor 3.

Subproblem 1

Set the factor '(5 + 7x + x2)' equal to zero and attempt to solve: Simplifying 5 + 7x + x2 = 0 Solving 5 + 7x + x2 = 0 Begin completing the square. Move the constant term to the right: Add '-5' to each side of the equation. 5 + 7x + -5 + x2 = 0 + -5 Reorder the terms: 5 + -5 + 7x + x2 = 0 + -5 Combine like terms: 5 + -5 = 0 0 + 7x + x2 = 0 + -5 7x + x2 = 0 + -5 Combine like terms: 0 + -5 = -5 7x + x2 = -5 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 = -5 + 12.25 Reorder the terms: 12.25 + 7x + x2 = -5 + 12.25 Combine like terms: -5 + 12.25 = 7.25 12.25 + 7x + x2 = 7.25 Factor a perfect square on the left side: (x + 3.5)(x + 3.5) = 7.25 Calculate the square root of the right side: 2.692582404 Break this problem into two subproblems by setting (x + 3.5) equal to 2.692582404 and -2.692582404.

Subproblem 1

x + 3.5 = 2.692582404 Simplifying x + 3.5 = 2.692582404 Reorder the terms: 3.5 + x = 2.692582404 Solving 3.5 + x = 2.692582404 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 = 2.692582404 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + x = 2.692582404 + -3.5 x = 2.692582404 + -3.5 Combine like terms: 2.692582404 + -3.5 = -0.807417596 x = -0.807417596 Simplifying x = -0.807417596

Subproblem 2

x + 3.5 = -2.692582404 Simplifying x + 3.5 = -2.692582404 Reorder the terms: 3.5 + x = -2.692582404 Solving 3.5 + x = -2.692582404 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 = -2.692582404 + -3.5 Combine like terms: 3.5 + -3.5 = 0.0 0.0 + x = -2.692582404 + -3.5 x = -2.692582404 + -3.5 Combine like terms: -2.692582404 + -3.5 = -6.192582404 x = -6.192582404 Simplifying x = -6.192582404

Solution

The solution to the problem is based on the solutions from the subproblems. x = {-0.807417596, -6.192582404}

Solution

x = {-0.807417596, -6.192582404}

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