3x^2+6=21

Solution for 3x^2+6=21 equation:

Simplifying
3x2 + 6 = 21

Reorder the terms:
6 + 3x2 = 21

Solving
6 + 3x2 = 21

Solving for variable 'x'.

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

Add '-6' to each side of the equation.
6 + -6 + 3x2 = 21 + -6

Combine like terms: 6 + -6 = 0
0 + 3x2 = 21 + -6
3x2 = 21 + -6

Combine like terms: 21 + -6 = 15
3x2 = 15

Divide each side by '3'.
x2 = 5

Simplifying
x2 = 5

Take the square root of each side:
x = {-2.236067978, 2.236067978}