z=7-z^2-z-18

Solution for z=7-z^2-z-18 equation:

Simplifying
z = 7 + -1z2 + -1z + -18

Reorder the terms:
z = 7 + -18 + -1z + -1z2

Combine like terms: 7 + -18 = -11
z = -11 + -1z + -1z2

Solving
z = -11 + -1z + -1z2

Solving for variable 'z'.

Reorder the terms:
11 + z + z + z2 = -11 + -1z + -1z2 + 11 + z + z2

Combine like terms: z + z = 2z
11 + 2z + z2 = -11 + -1z + -1z2 + 11 + z + z2

Reorder the terms:
11 + 2z + z2 = -11 + 11 + -1z + z + -1z2 + z2

Combine like terms: -11 + 11 = 0
11 + 2z + z2 = 0 + -1z + z + -1z2 + z2
11 + 2z + z2 = -1z + z + -1z2 + z2

Combine like terms: -1z + z = 0
11 + 2z + z2 = 0 + -1z2 + z2
11 + 2z + z2 = -1z2 + z2

Combine like terms: -1z2 + z2 = 0
11 + 2z + z2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-11' to each side of the equation.
11 + 2z + -11 + z2 = 0 + -11

Reorder the terms:
11 + -11 + 2z + z2 = 0 + -11

Combine like terms: 11 + -11 = 0
0 + 2z + z2 = 0 + -11
2z + z2 = 0 + -11

Combine like terms: 0 + -11 = -11
2z + z2 = -11

The z term is 2z.  Take half its coefficient (1).
Square it (1) and add it to both sides.

Add '1' to each side of the equation.
2z + 1 + z2 = -11 + 1

Reorder the terms:
1 + 2z + z2 = -11 + 1

Combine like terms: -11 + 1 = -10
1 + 2z + z2 = -10

Factor a perfect square on the left side:
(z + 1)(z + 1) = -10

Can't calculate square root of the right side.

The solution to this equation could not be determined.