(u+3)*7=42

Solution for (u+3)*7=42 equation:

Simplifying
(u + 3) * 7 = 42

Reorder the terms:
(3 + u) * 7 = 42

Reorder the terms for easier multiplication:
7(3 + u) = 42
(3 * 7 + u * 7) = 42
(21 + 7u) = 42

Solving
21 + 7u = 42

Solving for variable 'u'.

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

Add '-21' to each side of the equation.
21 + -21 + 7u = 42 + -21

Combine like terms: 21 + -21 = 0
0 + 7u = 42 + -21
7u = 42 + -21

Combine like terms: 42 + -21 = 21
7u = 21

Divide each side by '7'.
u = 3

Simplifying
u = 3