2x^2-5x-16=0

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Solution for 2x^2-5x-16=0 equation:


Simplifying
2x2 + -5x + -16 = 0

Reorder the terms:
-16 + -5x + 2x2 = 0

Solving
-16 + -5x + 2x2 = 0

Solving for variable 'x'.

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

Divide each side by '2'.
-8 + -2.5x + x2 = 0

Move the constant term to the right:

Add '8' to each side of the equation.
-8 + -2.5x + 8 + x2 = 0 + 8

Reorder the terms:
-8 + 8 + -2.5x + x2 = 0 + 8

Combine like terms: -8 + 8 = 0
0 + -2.5x + x2 = 0 + 8
-2.5x + x2 = 0 + 8

Combine like terms: 0 + 8 = 8
-2.5x + x2 = 8

The x term is -2.5x.  Take half its coefficient (-1.25).
Square it (1.5625) and add it to both sides.

Add '1.5625' to each side of the equation.
-2.5x + 1.5625 + x2 = 8 + 1.5625

Reorder the terms:
1.5625 + -2.5x + x2 = 8 + 1.5625

Combine like terms: 8 + 1.5625 = 9.5625
1.5625 + -2.5x + x2 = 9.5625

Factor a perfect square on the left side:
(x + -1.25)(x + -1.25) = 9.5625

Calculate the square root of the right side: 3.092329219

Break this problem into two subproblems by setting 
(x + -1.25) equal to 3.092329219 and -3.092329219.

Subproblem 1

x + -1.25 = 3.092329219 Simplifying x + -1.25 = 3.092329219 Reorder the terms: -1.25 + x = 3.092329219 Solving -1.25 + x = 3.092329219 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.25' to each side of the equation. -1.25 + 1.25 + x = 3.092329219 + 1.25 Combine like terms: -1.25 + 1.25 = 0.00 0.00 + x = 3.092329219 + 1.25 x = 3.092329219 + 1.25 Combine like terms: 3.092329219 + 1.25 = 4.342329219 x = 4.342329219 Simplifying x = 4.342329219

Subproblem 2

x + -1.25 = -3.092329219 Simplifying x + -1.25 = -3.092329219 Reorder the terms: -1.25 + x = -3.092329219 Solving -1.25 + x = -3.092329219 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '1.25' to each side of the equation. -1.25 + 1.25 + x = -3.092329219 + 1.25 Combine like terms: -1.25 + 1.25 = 0.00 0.00 + x = -3.092329219 + 1.25 x = -3.092329219 + 1.25 Combine like terms: -3.092329219 + 1.25 = -1.842329219 x = -1.842329219 Simplifying x = -1.842329219

Solution

The solution to the problem is based on the solutions from the subproblems. x = {4.342329219, -1.842329219}

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