0=-y^2-2y-40

Solution for 0=-y^2-2y-40 equation:

Simplifying
0 = -1y2 + -2y + -40

Reorder the terms:
0 = -40 + -2y + -1y2

Solving
0 = -40 + -2y + -1y2

Solving for variable 'y'.

Combine like terms: 0 + 40 = 40
40 + 2y + y2 = -40 + -2y + -1y2 + 40 + 2y + y2

Reorder the terms:
40 + 2y + y2 = -40 + 40 + -2y + 2y + -1y2 + y2

Combine like terms: -40 + 40 = 0
40 + 2y + y2 = 0 + -2y + 2y + -1y2 + y2
40 + 2y + y2 = -2y + 2y + -1y2 + y2

Combine like terms: -2y + 2y = 0
40 + 2y + y2 = 0 + -1y2 + y2
40 + 2y + y2 = -1y2 + y2

Combine like terms: -1y2 + y2 = 0
40 + 2y + y2 = 0

Begin completing the square.

Move the constant term to the right:

Add '-40' to each side of the equation.
40 + 2y + -40 + y2 = 0 + -40

Reorder the terms:
40 + -40 + 2y + y2 = 0 + -40

Combine like terms: 40 + -40 = 0
0 + 2y + y2 = 0 + -40
2y + y2 = 0 + -40

Combine like terms: 0 + -40 = -40
2y + y2 = -40

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

Add '1' to each side of the equation.
2y + 1 + y2 = -40 + 1

Reorder the terms:
1 + 2y + y2 = -40 + 1

Combine like terms: -40 + 1 = -39
1 + 2y + y2 = -39

Factor a perfect square on the left side:
(y + 1)(y + 1) = -39

Can't calculate square root of the right side.

The solution to this equation could not be determined.