#### (i) (3x – 1)^{2} – (3x – 2) (3x + 1)

#### (ii) (4x + 3y)^{2} – (4x – 3y)^{2} – 48xy

**Answer :**

**(i) (3x – 1)**^{2} – (3x – 2) (3x + 1)

^{2}– (3x – 2) (3x + 1)

It can be written as

= [(3x)^{2} + 1^{2} – 2 × 3x × 1] – [(3x)^{2} – (2 – 1) (3x) – 2 × 1]

By further calculation

= [9x^{2} + 1 – 6x] – [9x^{2} – 3x – 2]

So we get

= 9x^{2} + 1 – 6x – 9x^{2} + 3x + 2

= -3x + 3

= 3 – 3x

**(ii) (4x + 3y)**^{2} – (4x – 3y)^{2} – 48xy

^{2}– (4x – 3y)

^{2}– 48xy

It can be written as

= [(4x)^{2} + (3y)^{2} + 2 × 4x × 4y] – [(4x)^{2} + (3y)^{2} – 2 × 4x × 3y] – 48xy

By further calculation

= [16x^{2} + 9y^{2} + 24xy] – [16x^{2} + 9y^{2} – 24xy] – 48xy

So we get

= 16x^{2} + 9y^{2} + 24xy – 16x^{2} – 9y^{2} + 24xy – 48xy

= 0

**More Solutions:**

- Trigonometric Ratios of Standard Angles
- Find the value of A if
- Find the value of θ (0° < θ < 90°) if:
- If A, B and C are the interior angles of a △ ABC
- The value of tan 30/cot60 is
- The value of (sin 45 + cos 45 ) is
- The value of tan² 30 – 4 sin² 45 is
- If A = 30, then the value of 2 sin A Cos A is
- The value of (sin 30 + cos 30) – (sin 60 + cos 60) is
- The value of √3 cosec 60 – sec 60 is