2x^2+15x-18=0

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Solution for 2x^2+15x-18=0 equation:


Simplifying
2x2 + 15x + -18 = 0

Reorder the terms:
-18 + 15x + 2x2 = 0

Solving
-18 + 15x + 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'.
-9 + 7.5x + x2 = 0

Move the constant term to the right:

Add '9' to each side of the equation.
-9 + 7.5x + 9 + x2 = 0 + 9

Reorder the terms:
-9 + 9 + 7.5x + x2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + 7.5x + x2 = 0 + 9
7.5x + x2 = 0 + 9

Combine like terms: 0 + 9 = 9
7.5x + x2 = 9

The x term is 7.5x.  Take half its coefficient (3.75).
Square it (14.0625) and add it to both sides.

Add '14.0625' to each side of the equation.
7.5x + 14.0625 + x2 = 9 + 14.0625

Reorder the terms:
14.0625 + 7.5x + x2 = 9 + 14.0625

Combine like terms: 9 + 14.0625 = 23.0625
14.0625 + 7.5x + x2 = 23.0625

Factor a perfect square on the left side:
(x + 3.75)(x + 3.75) = 23.0625

Calculate the square root of the right side: 4.802343178

Break this problem into two subproblems by setting 
(x + 3.75) equal to 4.802343178 and -4.802343178.

Subproblem 1

x + 3.75 = 4.802343178 Simplifying x + 3.75 = 4.802343178 Reorder the terms: 3.75 + x = 4.802343178 Solving 3.75 + x = 4.802343178 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-3.75' to each side of the equation. 3.75 + -3.75 + x = 4.802343178 + -3.75 Combine like terms: 3.75 + -3.75 = 0.00 0.00 + x = 4.802343178 + -3.75 x = 4.802343178 + -3.75 Combine like terms: 4.802343178 + -3.75 = 1.052343178 x = 1.052343178 Simplifying x = 1.052343178

Subproblem 2

x + 3.75 = -4.802343178 Simplifying x + 3.75 = -4.802343178 Reorder the terms: 3.75 + x = -4.802343178 Solving 3.75 + x = -4.802343178 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-3.75' to each side of the equation. 3.75 + -3.75 + x = -4.802343178 + -3.75 Combine like terms: 3.75 + -3.75 = 0.00 0.00 + x = -4.802343178 + -3.75 x = -4.802343178 + -3.75 Combine like terms: -4.802343178 + -3.75 = -8.552343178 x = -8.552343178 Simplifying x = -8.552343178

Solution

The solution to the problem is based on the solutions from the subproblems. x = {1.052343178, -8.552343178}

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