a+b = √7 এবং a-b= √5 হলে, 8ab(a2+b2) = কত?
সমাধান
সঠিক উত্তর: Option B
8ab(a²+b² )
= 4ab.2(a²+b² )
= {(a+b)²-(a-b)²}{(a+b)²+(a-b)²}
= {(√7)²-(√5)²}{(√7)²+(√5)²}
= (7-5)(7+5)
= 2×12
= 24
= 4ab.2(a²+b² )
= {(a+b)²-(a-b)²}{(a+b)²+(a-b)²}
= {(√7)²-(√5)²}{(√7)²+(√5)²}
= (7-5)(7+5)
= 2×12
= 24
