x^2+2x^2-20=0

Solution for x^2+2x^2-20=0 equation:

Simplifying
x2 + 2x2 + -20 = 0

Reorder the terms:
-20 + x2 + 2x2 = 0

Combine like terms: x2 + 2x2 = 3x2
-20 + 3x2 = 0

Solving
-20 + 3x2 = 0

Solving for variable 'x'.

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

Add '20' to each side of the equation.
-20 + 20 + 3x2 = 0 + 20

Combine like terms: -20 + 20 = 0
0 + 3x2 = 0 + 20
3x2 = 0 + 20

Combine like terms: 0 + 20 = 20
3x2 = 20

Divide each side by '3'.
x2 = 6.666666667

Simplifying
x2 = 6.666666667

Take the square root of each side:
x = {-2.581988898, 2.581988898}