[a-11]*7=42

Solution for [a-11]*7=42 equation:

Simplifying
[a + -11] * 7 = 42

Reorder the terms:
[-11 + a] * 7 = 42

Reorder the terms for easier multiplication:
7[-11 + a] = 42
[-11 * 7 + a * 7] = 42
[-77 + 7a] = 42

Solving
-77 + 7a = 42

Solving for variable 'a'.

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

Add '77' to each side of the equation.
-77 + 77 + 7a = 42 + 77

Combine like terms: -77 + 77 = 0
0 + 7a = 42 + 77
7a = 42 + 77

Combine like terms: 42 + 77 = 119
7a = 119

Divide each side by '7'.
a = 17

Simplifying
a = 17