Question

On simplifying (√5+2)², we get :-

9

5+2√5

7+4√5

9+4√5

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Answer 1

Given :-

• (√5 + 2)²

Solution :-

Apply identify : (a + b)² = a² + b² + 2ab

→ (√5 + 2)²

→ (√5)² + (2)² + 2 × √5 + 2

→ 5 + 4 + 4√5

→ 9 + 4√5

Some Identities

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