2x^2=x-21

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


Simplifying
2x2 = x + -21

Reorder the terms:
2x2 = -21 + x

Solving
2x2 = -21 + x

Solving for variable 'x'.

Reorder the terms:
21 + -1x + 2x2 = -21 + x + 21 + -1x

Reorder the terms:
21 + -1x + 2x2 = -21 + 21 + x + -1x

Combine like terms: -21 + 21 = 0
21 + -1x + 2x2 = 0 + x + -1x
21 + -1x + 2x2 = x + -1x

Combine like terms: x + -1x = 0
21 + -1x + 2x2 = 0

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

Divide each side by '2'.
10.5 + -0.5x + x2 = 0

Move the constant term to the right:

Add '-10.5' to each side of the equation.
10.5 + -0.5x + -10.5 + x2 = 0 + -10.5

Reorder the terms:
10.5 + -10.5 + -0.5x + x2 = 0 + -10.5

Combine like terms: 10.5 + -10.5 = 0.0
0.0 + -0.5x + x2 = 0 + -10.5
-0.5x + x2 = 0 + -10.5

Combine like terms: 0 + -10.5 = -10.5
-0.5x + x2 = -10.5

The x term is -0.5x.  Take half its coefficient (-0.25).
Square it (0.0625) and add it to both sides.

Add '0.0625' to each side of the equation.
-0.5x + 0.0625 + x2 = -10.5 + 0.0625

Reorder the terms:
0.0625 + -0.5x + x2 = -10.5 + 0.0625

Combine like terms: -10.5 + 0.0625 = -10.4375
0.0625 + -0.5x + x2 = -10.4375

Factor a perfect square on the left side:
(x + -0.25)(x + -0.25) = -10.4375

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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