2x^2+17x+42=0

Solution for 2x^2+17x+42=0 equation:

Simplifying
2x2 + 17x + 42 = 0

Reorder the terms:
42 + 17x + 2x2 = 0

Solving
42 + 17x + 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'.
21 + 8.5x + x2 = 0

Move the constant term to the right:

Add '-21' to each side of the equation.
21 + 8.5x + -21 + x2 = 0 + -21

Reorder the terms:
21 + -21 + 8.5x + x2 = 0 + -21

Combine like terms: 21 + -21 = 0
0 + 8.5x + x2 = 0 + -21
8.5x + x2 = 0 + -21

Combine like terms: 0 + -21 = -21
8.5x + x2 = -21

The x term is 8.5x.  Take half its coefficient (4.25).
Square it (18.0625) and add it to both sides.

Add '18.0625' to each side of the equation.
8.5x + 18.0625 + x2 = -21 + 18.0625

Reorder the terms:
18.0625 + 8.5x + x2 = -21 + 18.0625

Combine like terms: -21 + 18.0625 = -2.9375
18.0625 + 8.5x + x2 = -2.9375

Factor a perfect square on the left side:
(x + 4.25)(x + 4.25) = -2.9375

Can't calculate square root of the right side.

The solution to this equation could not be determined.