2x^2-21x+9=

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Solution for 2x^2-21x+9= equation:


Simplifying
2x2 + -21x + 9 = 0

Reorder the terms:
9 + -21x + 2x2 = 0

Solving
9 + -21x + 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'.
4.5 + -10.5x + x2 = 0

Move the constant term to the right:

Add '-4.5' to each side of the equation.
4.5 + -10.5x + -4.5 + x2 = 0 + -4.5

Reorder the terms:
4.5 + -4.5 + -10.5x + x2 = 0 + -4.5

Combine like terms: 4.5 + -4.5 = 0.0
0.0 + -10.5x + x2 = 0 + -4.5
-10.5x + x2 = 0 + -4.5

Combine like terms: 0 + -4.5 = -4.5
-10.5x + x2 = -4.5

The x term is -10.5x.  Take half its coefficient (-5.25).
Square it (27.5625) and add it to both sides.

Add '27.5625' to each side of the equation.
-10.5x + 27.5625 + x2 = -4.5 + 27.5625

Reorder the terms:
27.5625 + -10.5x + x2 = -4.5 + 27.5625

Combine like terms: -4.5 + 27.5625 = 23.0625
27.5625 + -10.5x + x2 = 23.0625

Factor a perfect square on the left side:
(x + -5.25)(x + -5.25) = 23.0625

Calculate the square root of the right side: 4.802343178

Break this problem into two subproblems by setting 
(x + -5.25) equal to 4.802343178 and -4.802343178.

Subproblem 1

x + -5.25 = 4.802343178 Simplifying x + -5.25 = 4.802343178 Reorder the terms: -5.25 + x = 4.802343178 Solving -5.25 + x = 4.802343178 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '5.25' to each side of the equation. -5.25 + 5.25 + x = 4.802343178 + 5.25 Combine like terms: -5.25 + 5.25 = 0.00 0.00 + x = 4.802343178 + 5.25 x = 4.802343178 + 5.25 Combine like terms: 4.802343178 + 5.25 = 10.052343178 x = 10.052343178 Simplifying x = 10.052343178

Subproblem 2

x + -5.25 = -4.802343178 Simplifying x + -5.25 = -4.802343178 Reorder the terms: -5.25 + x = -4.802343178 Solving -5.25 + x = -4.802343178 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '5.25' to each side of the equation. -5.25 + 5.25 + x = -4.802343178 + 5.25 Combine like terms: -5.25 + 5.25 = 0.00 0.00 + x = -4.802343178 + 5.25 x = -4.802343178 + 5.25 Combine like terms: -4.802343178 + 5.25 = 0.447656822 x = 0.447656822 Simplifying x = 0.447656822

Solution

The solution to the problem is based on the solutions from the subproblems. x = {10.052343178, 0.447656822}

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