21x^2-40x+21=0

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Solution for 21x^2-40x+21=0 equation:


Simplifying
21x2 + -40x + 21 = 0

Reorder the terms:
21 + -40x + 21x2 = 0

Solving
21 + -40x + 21x2 = 0

Solving for variable 'x'.

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

Divide each side by '21'.
1 + -1.904761905x + x2 = 0

Move the constant term to the right:

Add '-1' to each side of the equation.
1 + -1.904761905x + -1 + x2 = 0 + -1

Reorder the terms:
1 + -1 + -1.904761905x + x2 = 0 + -1

Combine like terms: 1 + -1 = 0
0 + -1.904761905x + x2 = 0 + -1
-1.904761905x + x2 = 0 + -1

Combine like terms: 0 + -1 = -1
-1.904761905x + x2 = -1

The x term is -1.904761905x.  Take half its coefficient (-0.9523809525).
Square it (0.9070294787) and add it to both sides.

Add '0.9070294787' to each side of the equation.
-1.904761905x + 0.9070294787 + x2 = -1 + 0.9070294787

Reorder the terms:
0.9070294787 + -1.904761905x + x2 = -1 + 0.9070294787

Combine like terms: -1 + 0.9070294787 = -0.0929705213
0.9070294787 + -1.904761905x + x2 = -0.0929705213

Factor a perfect square on the left side:
(x + -0.9523809525)(x + -0.9523809525) = -0.0929705213

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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