2x^2-5=21

Solution for 2x^2-5=21 equation:

Simplifying
2x2 + -5 = 21

Reorder the terms:
-5 + 2x2 = 21

Solving
-5 + 2x2 = 21

Solving for variable 'x'.

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

Add '5' to each side of the equation.
-5 + 5 + 2x2 = 21 + 5

Combine like terms: -5 + 5 = 0
0 + 2x2 = 21 + 5
2x2 = 21 + 5

Combine like terms: 21 + 5 = 26
2x2 = 26

Divide each side by '2'.
x2 = 13

Simplifying
x2 = 13

Take the square root of each side:
x = {-3.605551275, 3.605551275}