0.3(x+20)+0.9x=42

Solution for 0.3(x+20)+0.9x=42 equation:

Simplifying
0.3(x + 20) + 0.9x = 42

Reorder the terms:
0.3(20 + x) + 0.9x = 42
(20 * 0.3 + x * 0.3) + 0.9x = 42
(6 + 0.3x) + 0.9x = 42

Combine like terms: 0.3x + 0.9x = 1.2x
6 + 1.2x = 42

Solving
6 + 1.2x = 42

Solving for variable 'x'.

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

Add '-6' to each side of the equation.
6 + -6 + 1.2x = 42 + -6

Combine like terms: 6 + -6 = 0
0 + 1.2x = 42 + -6
1.2x = 42 + -6

Combine like terms: 42 + -6 = 36
1.2x = 36

Divide each side by '1.2'.
x = 30

Simplifying
x = 30