x2 + 7xপ্রদত্ত রাশি: (x + 2) (x + 3) (x + 4 ) (x + 5) – 48
= (x + 2) (x + 5) (x + 3) (x + 4 ) - 48
= (x2 + 5x + 2x+10) (x2 + 4x + 3x + 12 ) - 48
= (x2 + 7x + 10) ( x2 + 7x + 12 ) – 48 [ a = x2 + 7x]
তাহলে, প্রদত্ত রাশি (a + 10) (a + 12 ) - 48
= a2 + 12a + 10a + 120 - 48
= a2 + 22a + 72
= a2 + 18a + 4a + 72
= a (a + 18 ) + 4 (a + 18 )
= (a + 18 ) (a + 4 )
= ( x2 + 7x + 18 ) ( x2 + 7x + 4 )
[ a = x2 + 7x]
= (x2 + 7x + 18) (x2 + 7x + 4 ) (Answer)