42=-7a

Solution for 42=-7a equation:

Simplifying
42 = -7a

Solving
42 = -7a

Solving for variable 'a'.

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

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

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

Add '-42' to each side of the equation.
42 + -42 + 7a = 0 + -42

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

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

Divide each side by '7'.
a = -6

Simplifying
a = -6