15x^2-45x-4=0

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Solution for 15x^2-45x-4=0 equation:


Simplifying
15x2 + -45x + -4 = 0

Reorder the terms:
-4 + -45x + 15x2 = 0

Solving
-4 + -45x + 15x2 = 0

Solving for variable 'x'.

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

Divide each side by '15'.
-0.2666666667 + -3x + x2 = 0

Move the constant term to the right:

Add '0.2666666667' to each side of the equation.
-0.2666666667 + -3x + 0.2666666667 + x2 = 0 + 0.2666666667

Reorder the terms:
-0.2666666667 + 0.2666666667 + -3x + x2 = 0 + 0.2666666667

Combine like terms: -0.2666666667 + 0.2666666667 = 0.0000000000
0.0000000000 + -3x + x2 = 0 + 0.2666666667
-3x + x2 = 0 + 0.2666666667

Combine like terms: 0 + 0.2666666667 = 0.2666666667
-3x + x2 = 0.2666666667

The x term is -3x.  Take half its coefficient (-1.5).
Square it (2.25) and add it to both sides.

Add '2.25' to each side of the equation.
-3x + 2.25 + x2 = 0.2666666667 + 2.25

Reorder the terms:
2.25 + -3x + x2 = 0.2666666667 + 2.25

Combine like terms: 0.2666666667 + 2.25 = 2.5166666667
2.25 + -3x + x2 = 2.5166666667

Factor a perfect square on the left side:
(x + -1.5)(x + -1.5) = 2.5166666667

Calculate the square root of the right side: 1.586400538

Break this problem into two subproblems by setting 
(x + -1.5) equal to 1.586400538 and -1.586400538.

Subproblem 1

x + -1.5 = 1.586400538 Simplifying x + -1.5 = 1.586400538 Reorder the terms: -1.5 + x = 1.586400538 Solving -1.5 + x = 1.586400538 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + x = 1.586400538 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + x = 1.586400538 + 1.5 x = 1.586400538 + 1.5 Combine like terms: 1.586400538 + 1.5 = 3.086400538 x = 3.086400538 Simplifying x = 3.086400538

Subproblem 2

x + -1.5 = -1.586400538 Simplifying x + -1.5 = -1.586400538 Reorder the terms: -1.5 + x = -1.586400538 Solving -1.5 + x = -1.586400538 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.5' to each side of the equation. -1.5 + 1.5 + x = -1.586400538 + 1.5 Combine like terms: -1.5 + 1.5 = 0.0 0.0 + x = -1.586400538 + 1.5 x = -1.586400538 + 1.5 Combine like terms: -1.586400538 + 1.5 = -0.086400538 x = -0.086400538 Simplifying x = -0.086400538

Solution

The solution to the problem is based on the solutions from the subproblems. x = {3.086400538, -0.086400538}

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