3x^2-13x+21=0

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Solution for 3x^2-13x+21=0 equation:


Simplifying
3x2 + -13x + 21 = 0

Reorder the terms:
21 + -13x + 3x2 = 0

Solving
21 + -13x + 3x2 = 0

Solving for variable 'x'.

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

Divide each side by '3'.
7 + -4.333333333x + x2 = 0

Move the constant term to the right:

Add '-7' to each side of the equation.
7 + -4.333333333x + -7 + x2 = 0 + -7

Reorder the terms:
7 + -7 + -4.333333333x + x2 = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -4.333333333x + x2 = 0 + -7
-4.333333333x + x2 = 0 + -7

Combine like terms: 0 + -7 = -7
-4.333333333x + x2 = -7

The x term is -4.333333333x.  Take half its coefficient (-2.166666667).
Square it (4.694444446) and add it to both sides.

Add '4.694444446' to each side of the equation.
-4.333333333x + 4.694444446 + x2 = -7 + 4.694444446

Reorder the terms:
4.694444446 + -4.333333333x + x2 = -7 + 4.694444446

Combine like terms: -7 + 4.694444446 = -2.305555554
4.694444446 + -4.333333333x + x2 = -2.305555554

Factor a perfect square on the left side:
(x + -2.166666667)(x + -2.166666667) = -2.305555554

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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