Find the sum and express it in simplest form

(7n^3-9n) + (-8n^3+6n-3)

Reorder the terms: 6 (-6 + 2n) + - 3 (7n + - 10) = - 9n + n (-6 * 6 + 2n * 6) + - 3 (7n + - 10) = - 9n + n (-36 + 12n) + - 3 (7n + - 10) = - 9n + n Reorder the terms: - 36 + 12n + - 3 (-10 + 7n) = - 9n + n - 36 + 12n + (-10 * - 3 + 7n * - 3) = - 9n + n - 36 + 12n + (30 + - 21n) = - 9n + n Reorder the terms: - 36 + 30 + 12n + - 21n = - 9n + n Combine like terms: - 36 + 30 = - 6 - 6 + 12n + - 21n = - 9n + n Combine like terms: 12n + - 21n = - 9n - 6 + - 9n = - 9n + n Combine like terms: - 9n + n = - 8n - 6 + - 9n = - 8n Solving - 6 + - 9n = - 8n Solving for variable 'n'. Move all terms containing n to the left, all other terms to the right. Add '8n' to each side of the equation. - 6 + - 9n + 8n = - 8n + 8n Combine like terms: - 9n + 8n = - 1n - 6 + - 1n = - 8n + 8n Combine like terms: - 8n + 8n = 0 - 6 + - 1n = 0 Add '6' to each side of the equation. - 6 + 6 + - 1n = 0 + 6 Combine like terms: - 6 + 6 = 0 0 + - 1n = 0 + 6 - 1n = 0 + 6 Combine like terms: 0 + 6 = 6 - 1n = 6 Divide each side by '-1'. n = - 6 Simplifying n = - 6