300=x(x*.2)

Solution for 300=x(x*.2) equation:

Simplifying
300 = x(x * 0.2)

Reorder the terms for easier multiplication:
300 = x(0.2x)

Remove parenthesis around (0.2x)
300 = x * 0.2x

Reorder the terms for easier multiplication:
300 = 0.2x * x

Multiply x * x
300 = 0.2x2

Solving
300 = 0.2x2

Solving for variable 'x'.

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

Add '-0.2x2' to each side of the equation.
300 + -0.2x2 = 0.2x2 + -0.2x2

Combine like terms: 0.2x2 + -0.2x2 = 0.0
300 + -0.2x2 = 0.0

Add '-300' to each side of the equation.
300 + -300 + -0.2x2 = 0.0 + -300

Combine like terms: 300 + -300 = 0
0 + -0.2x2 = 0.0 + -300
-0.2x2 = 0.0 + -300

Combine like terms: 0.0 + -300 = -300
-0.2x2 = -300

Divide each side by '-0.2'.
x2 = 1500

Simplifying
x2 = 1500

Take the square root of each side:
x = {-38.729833462, 38.729833462}