2(x*x)+13x+84=0

Solution for 2(x*x)+13x+84=0 equation:

Simplifying
2(x * x) + 13x + 84 = 0

Multiply x * x
2(x2) + 13x + 84 = 0

Reorder the terms:
84 + 13x + 2x2 = 0

Solving
84 + 13x + 2x2 = 0

Solving for variable 'x'.

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

Divide each side by '2'.
42 + 6.5x + x2 = 0

Move the constant term to the right:

Add '-42' to each side of the equation.
42 + 6.5x + -42 + x2 = 0 + -42

Reorder the terms:
42 + -42 + 6.5x + x2 = 0 + -42

Combine like terms: 42 + -42 = 0
0 + 6.5x + x2 = 0 + -42
6.5x + x2 = 0 + -42

Combine like terms: 0 + -42 = -42
6.5x + x2 = -42

The x term is 6.5x.  Take half its coefficient (3.25).
Square it (10.5625) and add it to both sides.

Add '10.5625' to each side of the equation.
6.5x + 10.5625 + x2 = -42 + 10.5625

Reorder the terms:
10.5625 + 6.5x + x2 = -42 + 10.5625

Combine like terms: -42 + 10.5625 = -31.4375
10.5625 + 6.5x + x2 = -31.4375

Factor a perfect square on the left side:
(x + 3.25)(x + 3.25) = -31.4375

Can't calculate square root of the right side.

The solution to this equation could not be determined.