(0.1x-0.3)(0.4-20)=0

Solution for (0.1x-0.3)(0.4-20)=0 equation:

Simplifying
(0.1x + -0.3)(0.4 + -20) = 0

Reorder the terms:
(-0.3 + 0.1x)(0.4 + -20) = 0

Combine like terms: 0.4 + -20 = -19.6
(-0.3 + 0.1x)(-19.6) = 0

Reorder the terms for easier multiplication:
-19.6(-0.3 + 0.1x) = 0
(-0.3 * -19.6 + 0.1x * -19.6) = 0
(5.88 + -1.96x) = 0

Solving
5.88 + -1.96x = 0

Solving for variable 'x'.

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

Add '-5.88' to each side of the equation.
5.88 + -5.88 + -1.96x = 0 + -5.88

Combine like terms: 5.88 + -5.88 = 0.00
0.00 + -1.96x = 0 + -5.88
-1.96x = 0 + -5.88

Combine like terms: 0 + -5.88 = -5.88
-1.96x = -5.88

Divide each side by '-1.96'.
x = 3

Simplifying
x = 3