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