-8x^2-14x-12=0

Solution for -8x^2-14x-12=0 equation:

Simplifying
-8x2 + -14x + -12 = 0

Reorder the terms:
-12 + -14x + -8x2 = 0

Solving
-12 + -14x + -8x2 = 0

Solving for variable 'x'.

Factor out the Greatest Common Factor (GCF), '-2'.
-2(6 + 7x + 4x2) = 0

Ignore the factor -2.
Subproblem 1
Set the factor '(6 + 7x + 4x2)' equal to zero and attempt to solve:

Simplifying
6 + 7x + 4x2 = 0

Solving
6 + 7x + 4x2 = 0

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

Divide each side by '4'.
1.5 + 1.75x + x2 = 0

Move the constant term to the right:

Add '-1.5' to each side of the equation.
1.5 + 1.75x + -1.5 + x2 = 0 + -1.5

Reorder the terms:
1.5 + -1.5 + 1.75x + x2 = 0 + -1.5

Combine like terms: 1.5 + -1.5 = 0.0
0.0 + 1.75x + x2 = 0 + -1.5
1.75x + x2 = 0 + -1.5

Combine like terms: 0 + -1.5 = -1.5
1.75x + x2 = -1.5

The x term is 1.75x.  Take half its coefficient (0.875).
Square it (0.765625) and add it to both sides.

Add '0.765625' to each side of the equation.
1.75x + 0.765625 + x2 = -1.5 + 0.765625

Reorder the terms:
0.765625 + 1.75x + x2 = -1.5 + 0.765625

Combine like terms: -1.5 + 0.765625 = -0.734375
0.765625 + 1.75x + x2 = -0.734375

Factor a perfect square on the left side:
(x + 0.875)(x + 0.875) = -0.734375

Can't calculate square root of the right side.

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.

The solution to this equation could not be determined.