.400(13.80-23.50)=x

Solution for .400(13.80-23.50)=x equation:

Simplifying
0.400(13.80 + -23.50) = x

Combine like terms: 13.80 + -23.50 = -9.7
0.400(-9.7) = x

Multiply 0.400 * -9.7
-3.88 = x

Solving
-3.88 = x

Solving for variable 'x'.

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

Add '-1x' to each side of the equation.
-3.88 + -1x = x + -1x

Combine like terms: x + -1x = 0
-3.88 + -1x = 0

Add '3.88' to each side of the equation.
-3.88 + 3.88 + -1x = 0 + 3.88

Combine like terms: -3.88 + 3.88 = 0.00
0.00 + -1x = 0 + 3.88
-1x = 0 + 3.88

Combine like terms: 0 + 3.88 = 3.88
-1x = 3.88

Divide each side by '-1'.
x = -3.88

Simplifying
x = -3.88