Which of the following is a factor of 1331x3 − 8y3?
4
11x − 2y
121x2 + 44xy + 4y2
121x2 − 22xy + 4y2

The factor is 11x - 2y ⇒ 2nd answer

Step-by-step explanation:

* Lets explain how to factorize the difference of two cubes

- If we want to factorize x³ - y³

- The binomial x³ - y³ is different of two cubes, because x³ is cube x

  and y³ is cube y

- The difference of two cubes has two factors one two two terms and

  the other is three terms

- To factorize it we find the ∛x³ and ∛y³

→ ∛x³ = x and ∛y³ = y

→ Then the first factor is (x - y)

→ We find the second factor from the first factor

→ square x

→ square y

→ Multiply x and y and put them between x² and y² with opposite sign

  of the first factor

→ The second factor is (x² + xy + y²)

* Lets do the same with 1331x³ - 8y³

∵

∵

∴ The first factor is (11x - 2y)

∵ (11x)² = 121x²

∵ (2y)² = 4y²

∵ 11x × 2y = 22xy

∵ The sign of first factor is (-)

∴ The second factor is (121x² + 22xy + 4y²)

∴ The factor is 11x - 2y  

8(-10x+3.5y-7)

8×-10x + 8×3.5y + 8×-7

-80x + 28y - 56

therefore

-80x+28y-56 is the correct answer