If `\ ^8C_r-\ ^7C_3\ =^7C_2\ fin d\ rdot`

If \ ^8C_r-\ ^7C_3\ =^7C_2\ find r

If ^(8)C_(r)-^(7)C_(3)^(7)C_(2)f in dr

Find r if ""^8C_r-""^7C_3=""^7C_2 .

If \ ^(15)C_(3r)=\ ^(15)C_(r+3) , find \ rdot

If ^15 C_(3r)=^(15)C_(r+3) , then find rdot

"^14C_5 + "^14C_6 + "^15C_7 + "^16C_8 = "^17C_r , then r =

If ^15 C_(3r):^(15)C_(r+1)=11 :3 , find the value of rdot

^8C_2+ ^8C_3+ ^8C_4+.... ^8C_7 is equal to

The coefficient of x^3y^4z in the expansion of (1+x+y-z)^9 is (A) 2.^9C_7.^7C_4 (B) -2.^9C_2 . ^7C_4 (C) ^9C_7.^7C_4 (D) none of these