42-3=13b

Solution for 42-3=13b equation:

Simplifying
42 + -3 = 13b

Combine like terms: 42 + -3 = 39
39 = 13b

Solving
39 = 13b

Solving for variable 'b'.

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

Add '-13b' to each side of the equation.
39 + -13b = 13b + -13b

Combine like terms: 13b + -13b = 0
39 + -13b = 0

Add '-39' to each side of the equation.
39 + -39 + -13b = 0 + -39

Combine like terms: 39 + -39 = 0
0 + -13b = 0 + -39
-13b = 0 + -39

Combine like terms: 0 + -39 = -39
-13b = -39

Divide each side by '-13'.
b = 3

Simplifying
b = 3