4a+6c = 3b-4r/3d, for a

5c2 (c + 10) + - 4 (2c2 + - 6c + 1) Reorder the terms: 5c2 (10 + c) + - 4 (2c2 + - 6c + 1) (10 * 5c2 + c * 5c2) + - 4 (2c2 + - 6c + 1) (50c2 + 5c3) + - 4 (2c2 + - 6c + 1) Reorder the terms: 50c2 + 5c3 + - 4 (1 + - 6c + 2c2) 50c2 + 5c3 + (1 * - 4 + - 6c * - 4 + 2c2 * - 4) 50c2 + 5c3 + (-4 + 24c + - 8c2) Reorder the terms: - 4 + 24c + 50c2 + - 8c2 + 5c3 Combine like terms: 50c2 + - 8c2 = 42c2 - 4 + 24c + 42c2 + 5c 3