16а² - 8а + 14b - 49b² = (16a² - 49b²) + (-8a + 14b) =
= ( (4a)² - (7b)² ) - 2(4a - 7b) = (4a - 7b)(4a + 7b) - 2(4a - 7b) =
= (4a - 7b)(4a + 7b - 2)
t³ - 21t - 7t² + 27 = (t³ + 27) + ( - 7t² - 21t) =
= (t³ + 3³) - 7t(t + 3) = (t +3)(t² - 3t + 3²) - 7t(t+3) =
= (t + 3)(t² - 3t + 9 - 7t) = (t + 3)( t² - 10t + 9) =
= (t + 3)(t² - t - 9t + 9) = (t + 3)( t(t - 1) - 9(t - 1) ) =
= (t + 3)(t - 1)( t - 9)