300=x(1.5x)

Solution for 300=x(1.5x) equation:

Simplifying
300 = x(1.5x)

Remove parenthesis around (1.5x)
300 = x * 1.5x

Reorder the terms for easier multiplication:
300 = 1.5x * x

Multiply x * x
300 = 1.5x2

Solving
300 = 1.5x2

Solving for variable 'x'.

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

Add '-1.5x2' to each side of the equation.
300 + -1.5x2 = 1.5x2 + -1.5x2

Combine like terms: 1.5x2 + -1.5x2 = 0.0
300 + -1.5x2 = 0.0

Add '-300' to each side of the equation.
300 + -300 + -1.5x2 = 0.0 + -300

Combine like terms: 300 + -300 = 0
0 + -1.5x2 = 0.0 + -300
-1.5x2 = 0.0 + -300

Combine like terms: 0.0 + -300 = -300
-1.5x2 = -300

Divide each side by '-1.5'.
x2 = 200

Simplifying
x2 = 200

Take the square root of each side:
x = {-14.142135624, 14.142135624}