81-42=w

Solution for 81-42=w equation:

Simplifying
81 + -42 = w

Combine like terms: 81 + -42 = 39
39 = w

Solving
39 = w

Solving for variable 'w'.

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

Add '-1w' to each side of the equation.
39 + -1w = w + -1w

Combine like terms: w + -1w = 0
39 + -1w = 0

Add '-39' to each side of the equation.
39 + -39 + -1w = 0 + -39

Combine like terms: 39 + -39 = 0
0 + -1w = 0 + -39
-1w = 0 + -39

Combine like terms: 0 + -39 = -39
-1w = -39

Divide each side by '-1'.
w = 39

Simplifying
w = 39