105=3y^2+21

Solution for 105=3y^2+21 equation:

Simplifying
105 = 3y2 + 21

Reorder the terms:
105 = 21 + 3y2

Solving
105 = 21 + 3y2

Solving for variable 'y'.

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

Add '-3y2' to each side of the equation.
105 + -3y2 = 21 + 3y2 + -3y2

Combine like terms: 3y2 + -3y2 = 0
105 + -3y2 = 21 + 0
105 + -3y2 = 21

Add '-105' to each side of the equation.
105 + -105 + -3y2 = 21 + -105

Combine like terms: 105 + -105 = 0
0 + -3y2 = 21 + -105
-3y2 = 21 + -105

Combine like terms: 21 + -105 = -84
-3y2 = -84

Divide each side by '-3'.
y2 = 28

Simplifying
y2 = 28

Take the square root of each side:
y = {-5.291502622, 5.291502622}