Difference of cubes is </span>a³ - b³.<span> 27 can be written as 3</span>³ (= 3 × 3 × 3 = 27). So, a = 3. 8 can be written as 2³ (= 2 × 2 × 2 = 8). So, b = 2.
Difference of cubes can be expressed as: a³ - b³ = (a - b)(a² + ab + b²) ⇒ 3³ - 2³ = (3 - 2)(3² + 3×2 + 2²) = 1 × (9 + 6 + 4) = 1 × 19 = 19 ⇒ 27 - 8 = 19
