20x^2+18x+21=0

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Solution for 20x^2+18x+21=0 equation:


Simplifying
20x2 + 18x + 21 = 0

Reorder the terms:
21 + 18x + 20x2 = 0

Solving
21 + 18x + 20x2 = 0

Solving for variable 'x'.

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

Divide each side by '20'.
1.05 + 0.9x + x2 = 0

Move the constant term to the right:

Add '-1.05' to each side of the equation.
1.05 + 0.9x + -1.05 + x2 = 0 + -1.05

Reorder the terms:
1.05 + -1.05 + 0.9x + x2 = 0 + -1.05

Combine like terms: 1.05 + -1.05 = 0.00
0.00 + 0.9x + x2 = 0 + -1.05
0.9x + x2 = 0 + -1.05

Combine like terms: 0 + -1.05 = -1.05
0.9x + x2 = -1.05

The x term is 0.9x.  Take half its coefficient (0.45).
Square it (0.2025) and add it to both sides.

Add '0.2025' to each side of the equation.
0.9x + 0.2025 + x2 = -1.05 + 0.2025

Reorder the terms:
0.2025 + 0.9x + x2 = -1.05 + 0.2025

Combine like terms: -1.05 + 0.2025 = -0.8475
0.2025 + 0.9x + x2 = -0.8475

Factor a perfect square on the left side:
(x + 0.45)(x + 0.45) = -0.8475

Can't calculate square root of the right side.

The solution to this equation could not be determined.

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