x(x+3x)=1.25

Solution for x(x+3x)=1.25 equation:

Simplifying
x(x + 3x) = 1.25

Combine like terms: x + 3x = 4x
x(4x) = 1.25

Remove parenthesis around (4x)
x * 4x = 1.25

Reorder the terms for easier multiplication:
4x * x = 1.25

Multiply x * x
4x2 = 1.25

Solving
4x2 = 1.25

Solving for variable 'x'.

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

Divide each side by '4'.
x2 = 0.3125

Simplifying
x2 = 0.3125

Take the square root of each side:
x = {-0.559016994, 0.559016994}