যদি x2+1x2=38 হয়, তবে, x-1x=?
A
±40
B
±6
C
±7
D
±5
Correct Answer: ±6
x2 + 1x2 = 38⇒(x - 1x)2 + 2.x.1x = 38⇒(x - 1x)2 = 36.'. x - 1x = ±6