3(5x-x)-3(1-2x)=42

Solution for 3(5x-x)-3(1-2x)=42 equation:

Simplifying
3(5x + -1x) + -3(1 + -2x) = 42

Combine like terms: 5x + -1x = 4x
3(4x) + -3(1 + -2x) = 42

Remove parenthesis around (4x)
3 * 4x + -3(1 + -2x) = 42

Multiply 3 * 4
12x + -3(1 + -2x) = 42
12x + (1 * -3 + -2x * -3) = 42
12x + (-3 + 6x) = 42

Reorder the terms:
-3 + 12x + 6x = 42

Combine like terms: 12x + 6x = 18x
-3 + 18x = 42

Solving
-3 + 18x = 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 + 18x = 42 + 3

Combine like terms: -3 + 3 = 0
0 + 18x = 42 + 3
18x = 42 + 3

Combine like terms: 42 + 3 = 45
18x = 45

Divide each side by '18'.
x = 2.5

Simplifying
x = 2.5