5x(2-5x)=15

Solution for 5x(2-5x)=15 equation:

Simplifying
5x(2 + -5x) = 15
(2 * 5x + -5x * 5x) = 15
(10x + -25x2) = 15

Solving
10x + -25x2 = 15

Solving for variable 'x'.

Reorder the terms:
-15 + 10x + -25x2 = 15 + -15

Combine like terms: 15 + -15 = 0
-15 + 10x + -25x2 = 0

Factor out the Greatest Common Factor (GCF), '5'.
5(-3 + 2x + -5x2) = 0

Ignore the factor 5.
Subproblem 1
Set the factor '(-3 + 2x + -5x2)' equal to zero and attempt to solve:

Simplifying
-3 + 2x + -5x2 = 0

Solving
-3 + 2x + -5x2 = 0

Begin completing the square.  Divide all terms by
-5 the coefficient of the squared term: 

Divide each side by '-5'.
0.6 + -0.4x + x2 = 0

Move the constant term to the right:

Add '-0.6' to each side of the equation.
0.6 + -0.4x + -0.6 + x2 = 0 + -0.6

Reorder the terms:
0.6 + -0.6 + -0.4x + x2 = 0 + -0.6

Combine like terms: 0.6 + -0.6 = 0.0
0.0 + -0.4x + x2 = 0 + -0.6
-0.4x + x2 = 0 + -0.6

Combine like terms: 0 + -0.6 = -0.6
-0.4x + x2 = -0.6

The x term is -0.4x.  Take half its coefficient (-0.2).
Square it (0.04) and add it to both sides.

Add '0.04' to each side of the equation.
-0.4x + 0.04 + x2 = -0.6 + 0.04

Reorder the terms:
0.04 + -0.4x + x2 = -0.6 + 0.04

Combine like terms: -0.6 + 0.04 = -0.56
0.04 + -0.4x + x2 = -0.56

Factor a perfect square on the left side:
(x + -0.2)(x + -0.2) = -0.56

Can't calculate square root of the right side.

The solution to this equation could not be determined.

This subproblem is being ignored because a solution could not be determined.

The solution to this equation could not be determined.