x + y = 4 এবং x - y = 3 হলে 8xy = কত?

A 3

B 7

C 14

D 17

Correct Answer: Option C

দেওয়া আছে, x + y = 4
x - y = 3

8xy = 2{(x + y)² - (x - y)²}
= 2{4² - 3²}
= 2(16 - 9)
= 2 × 7
= 14