4x^2-6x-15=0

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Solution for 4x^2-6x-15=0 equation:


Simplifying
4x2 + -6x + -15 = 0

Reorder the terms:
-15 + -6x + 4x2 = 0

Solving
-15 + -6x + 4x2 = 0

Solving for variable 'x'.

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

Divide each side by '4'.
-3.75 + -1.5x + x2 = 0

Move the constant term to the right:

Add '3.75' to each side of the equation.
-3.75 + -1.5x + 3.75 + x2 = 0 + 3.75

Reorder the terms:
-3.75 + 3.75 + -1.5x + x2 = 0 + 3.75

Combine like terms: -3.75 + 3.75 = 0.00
0.00 + -1.5x + x2 = 0 + 3.75
-1.5x + x2 = 0 + 3.75

Combine like terms: 0 + 3.75 = 3.75
-1.5x + x2 = 3.75

The x term is -1.5x.  Take half its coefficient (-0.75).
Square it (0.5625) and add it to both sides.

Add '0.5625' to each side of the equation.
-1.5x + 0.5625 + x2 = 3.75 + 0.5625

Reorder the terms:
0.5625 + -1.5x + x2 = 3.75 + 0.5625

Combine like terms: 3.75 + 0.5625 = 4.3125
0.5625 + -1.5x + x2 = 4.3125

Factor a perfect square on the left side:
(x + -0.75)(x + -0.75) = 4.3125

Calculate the square root of the right side: 2.076655966

Break this problem into two subproblems by setting 
(x + -0.75) equal to 2.076655966 and -2.076655966.

Subproblem 1

x + -0.75 = 2.076655966 Simplifying x + -0.75 = 2.076655966 Reorder the terms: -0.75 + x = 2.076655966 Solving -0.75 + x = 2.076655966 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.75' to each side of the equation. -0.75 + 0.75 + x = 2.076655966 + 0.75 Combine like terms: -0.75 + 0.75 = 0.00 0.00 + x = 2.076655966 + 0.75 x = 2.076655966 + 0.75 Combine like terms: 2.076655966 + 0.75 = 2.826655966 x = 2.826655966 Simplifying x = 2.826655966

Subproblem 2

x + -0.75 = -2.076655966 Simplifying x + -0.75 = -2.076655966 Reorder the terms: -0.75 + x = -2.076655966 Solving -0.75 + x = -2.076655966 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '0.75' to each side of the equation. -0.75 + 0.75 + x = -2.076655966 + 0.75 Combine like terms: -0.75 + 0.75 = 0.00 0.00 + x = -2.076655966 + 0.75 x = -2.076655966 + 0.75 Combine like terms: -2.076655966 + 0.75 = -1.326655966 x = -1.326655966 Simplifying x = -1.326655966

Solution

The solution to the problem is based on the solutions from the subproblems. x = {2.826655966, -1.326655966}

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