39=0.1(x^2)

Solution for 39=0.1(x^2) equation:

Simplifying
39 = 0.1(x2)

Solving
39 = 0.1x2

Solving for variable 'x'.

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

Add '-0.1x2' to each side of the equation.
39 + -0.1x2 = 0.1x2 + -0.1x2

Combine like terms: 0.1x2 + -0.1x2 = 0.0
39 + -0.1x2 = 0.0

Add '-39' to each side of the equation.
39 + -39 + -0.1x2 = 0.0 + -39

Combine like terms: 39 + -39 = 0
0 + -0.1x2 = 0.0 + -39
-0.1x2 = 0.0 + -39

Combine like terms: 0.0 + -39 = -39
-0.1x2 = -39

Divide each side by '-0.1'.
x2 = 390

Simplifying
x2 = 390

Take the square root of each side:
x = {-19.748417658, 19.748417658}