y^2-18+81-72=0

Solution for y^2-18+81-72=0 equation:

Simplifying
y2 + -18 + 81 + -72 = 0

Reorder the terms:
-18 + 81 + -72 + y2 = 0

Combine like terms: -18 + 81 = 63
63 + -72 + y2 = 0

Combine like terms: 63 + -72 = -9
-9 + y2 = 0

Solving
-9 + y2 = 0

Solving for variable 'y'.

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

Add '9' to each side of the equation.
-9 + 9 + y2 = 0 + 9

Combine like terms: -9 + 9 = 0
0 + y2 = 0 + 9
y2 = 0 + 9

Combine like terms: 0 + 9 = 9
y2 = 9

Simplifying
y2 = 9

Take the square root of each side:
y = {-3, 3}