(1-y)y=1

Solution for (1-y)y=1 equation:

Simplifying
(1 + -1y) * y = 1

Reorder the terms for easier multiplication:
y(1 + -1y) = 1
(1 * y + -1y * y) = 1
(1y + -1y2) = 1

Solving
1y + -1y2 = 1

Solving for variable 'y'.

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

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

Begin completing the square.  Divide all terms by
-1 the coefficient of the squared term: 

Divide each side by '-1'.
1 + -1y + y2 = 0

Move the constant term to the right:

Add '-1' to each side of the equation.
1 + -1y + -1 + y2 = 0 + -1

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

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

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

The y term is -1y.  Take half its coefficient (-0.5).
Square it (0.25) and add it to both sides.

Add '0.25' to each side of the equation.
-1y + 0.25 + y2 = -1 + 0.25

Reorder the terms:
0.25 + -1y + y2 = -1 + 0.25

Combine like terms: -1 + 0.25 = -0.75
0.25 + -1y + y2 = -0.75

Factor a perfect square on the left side:
(y + -0.5)(y + -0.5) = -0.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.