(9-y^2)+y=72

Solution for (9-y^2)+y=72 equation:

Simplifying
(9 + -1y2) + y = 72

Remove parenthesis around (9 + -1y2)
9 + -1y2 + y = 72

Reorder the terms:
9 + y + -1y2 = 72

Solving
9 + y + -1y2 = 72

Solving for variable 'y'.

Reorder the terms:
9 + -72 + y + -1y2 = 72 + -72

Combine like terms: 9 + -72 = -63
-63 + y + -1y2 = 72 + -72

Combine like terms: 72 + -72 = 0
-63 + y + -1y2 = 0

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

Divide each side by '-1'.
63 + -1y + y2 = 0

Move the constant term to the right:

Add '-63' to each side of the equation.
63 + -1y + -63 + y2 = 0 + -63

Reorder the terms:
63 + -63 + -1y + y2 = 0 + -63

Combine like terms: 63 + -63 = 0
0 + -1y + y2 = 0 + -63
-1y + y2 = 0 + -63

Combine like terms: 0 + -63 = -63
-1y + y2 = -63

The y term is y.  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 = -63 + 0.25

Reorder the terms:
0.25 + -1y + y2 = -63 + 0.25

Combine like terms: -63 + 0.25 = -62.75
0.25 + -1y + y2 = -62.75

Factor a perfect square on the left side:
(y + 0.5)(y + 0.5) = -62.75

Can't calculate square root of the right side.

The solution to this equation could not be determined.