Question

81xsq-198xy+121ysq factorise the following​

Answer 1

Solution:

Given expression,

= 81x² - 198xy + 121y²

This can be written as,

= (9x)² - 2 × (9x) × (11y) + (11y)²

Now, we know that,

→ (a - b)² = a² - 2ab + b²

Also, the given expression is in the form of (a - b)². Thus,

= (9x - 11y)² which is the required answer.

Answer:

• Factorised form - (9x - 11y)².

Additional Identities:

• (a - b)² = a² - 2ab + b²
• a² - b² = (a + b)(a - b)
• (a + b)³ = a³ + 3ab(a + b) + b³
• (a - b)³ = a³ - 3ab(a - b) - b³
• a³ + b³ = (a + b)(a² - ab + b²)
• a³ - b³ = (a - b)(a² + ab + b²)

•••♪