39=-2(a+3)-7a

Solution for 39=-2(a+3)-7a equation:

Simplifying
39 = -2(a + 3) + -7a

Reorder the terms:
39 = -2(3 + a) + -7a
39 = (3 * -2 + a * -2) + -7a
39 = (-6 + -2a) + -7a

Combine like terms: -2a + -7a = -9a
39 = -6 + -9a

Solving
39 = -6 + -9a

Solving for variable 'a'.

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

Add '9a' to each side of the equation.
39 + 9a = -6 + -9a + 9a

Combine like terms: -9a + 9a = 0
39 + 9a = -6 + 0
39 + 9a = -6

Add '-39' to each side of the equation.
39 + -39 + 9a = -6 + -39

Combine like terms: 39 + -39 = 0
0 + 9a = -6 + -39
9a = -6 + -39

Combine like terms: -6 + -39 = -45
9a = -45

Divide each side by '9'.
a = -5

Simplifying
a = -5