Simplifying 15 + 5x = 0 Solving 15 + 5x = 0 Solving for variable 'x'. Move all terms containing x to the left, all other terms to the right. Add '-15' to each side of the equation. 15 + -15 + 5x = 0 + -15 Combine like terms: 15 + -15 = 0 0 + 5x = 0 + -15 5x = 0 + -15 Combine like terms: 0 + -15 = -15 5x = -15 Divide each side by '5'. x = -3 Simplifying x = -3