x+(x+3)=42

Solution for x+(x+3)=42 equation:

Simplifying
x + (x + 3) = 42

Reorder the terms:
x + (3 + x) = 42

Remove parenthesis around (3 + x)
x + 3 + x = 42

Reorder the terms:
3 + x + x = 42

Combine like terms: x + x = 2x
3 + 2x = 42

Solving
3 + 2x = 42

Solving for variable 'x'.

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

Add '-3' to each side of the equation.
3 + -3 + 2x = 42 + -3

Combine like terms: 3 + -3 = 0
0 + 2x = 42 + -3
2x = 42 + -3

Combine like terms: 42 + -3 = 39
2x = 39

Divide each side by '2'.
x = 19.5

Simplifying
x = 19.5