3y^2-9-12=0

Solution for 3y^2-9-12=0 equation:

Simplifying
3y2 + -9 + -12 = 0

Reorder the terms:
-9 + -12 + 3y2 = 0

Combine like terms: -9 + -12 = -21
-21 + 3y2 = 0

Solving
-21 + 3y2 = 0

Solving for variable 'y'.

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

Add '21' to each side of the equation.
-21 + 21 + 3y2 = 0 + 21

Combine like terms: -21 + 21 = 0
0 + 3y2 = 0 + 21
3y2 = 0 + 21

Combine like terms: 0 + 21 = 21
3y2 = 21

Divide each side by '3'.
y2 = 7

Simplifying
y2 = 7

Take the square root of each side:
y = {-2.645751311, 2.645751311}