z^2+12z-11=0

Solution for z^2+12z-11=0 equation:

Simplifying
z2 + 12z + -11 = 0

Reorder the terms:
-11 + 12z + z2 = 0

Solving
-11 + 12z + z2 = 0

Solving for variable 'z'.

Begin completing the square.

Move the constant term to the right:

Add '11' to each side of the equation.
-11 + 12z + 11 + z2 = 0 + 11

Reorder the terms:
-11 + 11 + 12z + z2 = 0 + 11

Combine like terms: -11 + 11 = 0
0 + 12z + z2 = 0 + 11
12z + z2 = 0 + 11

Combine like terms: 0 + 11 = 11
12z + z2 = 11

The z term is 12z.  Take half its coefficient (6).
Square it (36) and add it to both sides.

Add '36' to each side of the equation.
12z + 36 + z2 = 11 + 36

Reorder the terms:
36 + 12z + z2 = 11 + 36

Combine like terms: 11 + 36 = 47
36 + 12z + z2 = 47

Factor a perfect square on the left side:
(z + 6)(z + 6) = 47

Calculate the square root of the right side: 6.8556546

Break this problem into two subproblems by setting 
(z + 6) equal to 6.8556546 and -6.8556546.

Subproblem 1
z + 6 = 6.8556546

Simplifying
z + 6 = 6.8556546

Reorder the terms:
6 + z = 6.8556546

Solving
6 + z = 6.8556546

Solving for variable 'z'.

Move all terms containing z to the left, all other terms to the right.

Add '-6' to each side of the equation.
6 + -6 + z = 6.8556546 + -6

Combine like terms: 6 + -6 = 0
0 + z = 6.8556546 + -6
z = 6.8556546 + -6

Combine like terms: 6.8556546 + -6 = 0.8556546
z = 0.8556546

Simplifying
z = 0.8556546

Subproblem 2
z + 6 = -6.8556546

Simplifying
z + 6 = -6.8556546

Reorder the terms:
6 + z = -6.8556546

Solving
6 + z = -6.8556546

Solving for variable 'z'.

Move all terms containing z to the left, all other terms to the right.

Add '-6' to each side of the equation.
6 + -6 + z = -6.8556546 + -6

Combine like terms: 6 + -6 = 0
0 + z = -6.8556546 + -6
z = -6.8556546 + -6

Combine like terms: -6.8556546 + -6 = -12.8556546
z = -12.8556546

Simplifying
z = -12.8556546

Solution
The solution to the problem is based on the solutions
from the subproblems.
z = {0.8556546, -12.8556546}