#### (i) (5x – 3y)^{3}

#### (ii) (2x – 1/3y)^{3}

**Answer :**

**(i) (5x – 3y)**^{3}

^{3}

It can be written as

= (5x)^{3} – (3y)^{3} – 3 × 5x × 3y (5x – 3y)

By further calculation

= 125x^{3} – 27y^{3} – 45xy (5x – 3y)

So we get

= 125x^{3} – 27y^{3} – 225x^{2}y + 135xy^{2}

**(ii) (2x – 1/3y)**^{3}

^{3}

It can be written as

= (2x)^{3} – (1/3y)^{3} – 3 × 2x × 1/3y (2x – 1/3y)

By further calculation

= 8x^{3} – 1/27y^{3} – 2x/y (2x – 1/3y)

So we get

= 8x^{3} – 1/27y^{3} – 4x^{2}/y + 2x/3y^{2}

**More Solutions:**

- Simplify the following (a + b)2 + (a – b)2
- Simplify the following (a + 1/a)2 + (a – 1/a)2
- Simplify the following (3x – 1)2 – (3x – 2) (3x + 1)
- Simplify the following (7p + 9q) (7p – 9q)
- Simplify the following (2x – y + 3) (2x – y – 3)
- Simplify the following (x + 2/x – 3) (x – 2/x – 3)
- Simplify the following (x + 2y + 3) (x + 2y + 7)
- Simplify the following (2p + 3q) (4p2 – 6pq + 9q2)
- Simplify the following (3p – 4q) (9p2 + 12pq + 16q2)
- Simplify the following (2x + 3y + 4z)