Question

simplify (2√3+√5)(2√3-√5)​

Answer 1

as we know that, a²-b² = (a+b)(a-b) or (a+b)(a-b) = a²-b²

therefore let 2√3 be a and 5 be b so we infer that the above formula is also in the form of (a+b)(a-b)

so (a+b)(a-b) = a²-b² = (2√3)² - (√5)²

2√3 × 2√3 = 2×2×√3×√3 = 4×3= 12

√5×√5= 5

so a²-b² = 12 -5 = 7

Answer 2

Answer:

7 is the required answer.

⇒(2√3(2√3-√5)+√5(2√3-√5)

⇒(12-2√15)+(2√15-5)

⇒(12-2√15)+2√15-5)

⇒12-5=7