4x^2+28x+81=0

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Solution for 4x^2+28x+81=0 equation:


Simplifying
4x2 + 28x + 81 = 0

Reorder the terms:
81 + 28x + 4x2 = 0

Solving
81 + 28x + 4x2 = 0

Solving for variable 'x'.

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

Divide each side by '4'.
20.25 + 7x + x2 = 0

Move the constant term to the right:

Add '-20.25' to each side of the equation.
20.25 + 7x + -20.25 + x2 = 0 + -20.25

Reorder the terms:
20.25 + -20.25 + 7x + x2 = 0 + -20.25

Combine like terms: 20.25 + -20.25 = 0.00
0.00 + 7x + x2 = 0 + -20.25
7x + x2 = 0 + -20.25

Combine like terms: 0 + -20.25 = -20.25
7x + x2 = -20.25

The x term is 7x.  Take half its coefficient (3.5).
Square it (12.25) and add it to both sides.

Add '12.25' to each side of the equation.
7x + 12.25 + x2 = -20.25 + 12.25

Reorder the terms:
12.25 + 7x + x2 = -20.25 + 12.25

Combine like terms: -20.25 + 12.25 = -8
12.25 + 7x + x2 = -8

Factor a perfect square on the left side:
(x + 3.5)(x + 3.5) = -8

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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