2x^2+21=81

Solution for 2x^2+21=81 equation:

Simplifying
2x2 + 21 = 81

Reorder the terms:
21 + 2x2 = 81

Solving
21 + 2x2 = 81

Solving for variable 'x'.

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

Add '-21' to each side of the equation.
21 + -21 + 2x2 = 81 + -21

Combine like terms: 21 + -21 = 0
0 + 2x2 = 81 + -21
2x2 = 81 + -21

Combine like terms: 81 + -21 = 60
2x2 = 60

Divide each side by '2'.
x2 = 30

Simplifying
x2 = 30

Take the square root of each side:
x = {-5.477225575, 5.477225575}