a^3 - 6a^2 - a + 30 = a^2a−6a - 6a−6 - 1a−6a - 6a−6 = a−6a - 6a−6a2−1a^2 - 1a2−1 = a−6a - 6a−6a+1a + 1a+1a−1a - 1a−1
a^3 - 6a^2 - a + 30 = a^2a−6a - 6a−6 - 1a−6a - 6a−6 = a−6a - 6a−6a2−1a^2 - 1a2−1 = a−6a - 6a−6a+1a + 1a+1a−1a - 1a−1