42=.8(x)

Solution for 42=.8(x) equation:

Simplifying
42 = 0.8(x)

Solving
42 = 0.8x

Solving for variable 'x'.

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

Add '-0.8x' to each side of the equation.
42 + -0.8x = 0.8x + -0.8x

Combine like terms: 0.8x + -0.8x = 0.0
42 + -0.8x = 0.0

Add '-42' to each side of the equation.
42 + -42 + -0.8x = 0.0 + -42

Combine like terms: 42 + -42 = 0
0 + -0.8x = 0.0 + -42
-0.8x = 0.0 + -42

Combine like terms: 0.0 + -42 = -42
-0.8x = -42

Divide each side by '-0.8'.
x = 52.5

Simplifying
x = 52.5