x2 + y2 = 25 এবং xy = 12 হলে x + y = ?
A
6
B
7
C
8
D
9
Correct Answer: 7
দেওয়া আছে - x2 + y23 = 25এবং xy = 12: (x + y)2 = x2 + 2xy + y2 = x2 + y2 + 2xy = 25 + 2.12 = 25 + 24(x + y)2 = 49x + y = 7