Verified Answer :

Simplifying
6k + -9 = -15

Reorder the terms:
-9 + 6k = -15

Solving
-9 + 6k = -15

Solving for variable 'k'.

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

Add '9' to each side of the equation.
-9 + 9 + 6k = -15 + 9

Combine like terms: -9 + 9 = 0
0 + 6k = -15 + 9
6k = -15 + 9

Combine like terms: -15 + 9 = -6
6k = -6

Divide each side by '6'.
k = -1