Question

please tell me fast (i) and. (ii)​

Answer 1

i) 7

ii) 23 + 4√15

Step-by-step explanation:

i) (2√3 + √5)(2√3 - √5)

=> (2√3)² - (√5)² { a² - b² = (a+b)(a-b) }

=> (4×3) - 5

=> 12 - 5

=> 7

ii) (√3 + 2√5)²

=> (√3)² + 2×√3×2√5 + (2√5)²

{ (a+b)² = a² + 2ab + b²}

=> 3 + 4√15 + 4×5

=> 3 + 4√15 + 20

=> 23 + 4√15