2x^2-21-5=0

Solution for 2x^2-21-5=0 equation:

Simplifying
2x2 + -21 + -5 = 0

Reorder the terms:
-21 + -5 + 2x2 = 0

Combine like terms: -21 + -5 = -26
-26 + 2x2 = 0

Solving
-26 + 2x2 = 0

Solving for variable 'x'.

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

Add '26' to each side of the equation.
-26 + 26 + 2x2 = 0 + 26

Combine like terms: -26 + 26 = 0
0 + 2x2 = 0 + 26
2x2 = 0 + 26

Combine like terms: 0 + 26 = 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}