Find the value of `.^9 C_3`

Find the value of .^9 C_6

Find the value of .^9 C_2

Find the value of .^6 C_3

Find the value of .^9P_4

Find the values of .^(9)C_(7)

Find the value of .^20 C_0-(.^20C_1)/2+(.^20C_2)/3-(.^20C_3)/4+...

Find the value of .^(20)C_(0) xx .^(13)C_(10) - .^(20)C_(1) xx .^(12)C_(9) + .^(20)C_(2) xx .^(11)C_(8) - "……" + .^(20)C_(10) .

Find the value of 3^2/3. 3^2/9. 3^2/27 …..

Find the value of 5C_3 + 4C_2

underset(x to -a)"Lt" (x^9+a^9)/(x+a) = 9 , then find the value of a.