Answer
28
Work Step by Step
Use the formula of combination: $_{n}$C$_{r}$=$\frac{n!}{r!(n-r)!}$. Plug in 8 for N and 2 for R:
$_{n}$C$_{r}$=$\frac{n!}{r!(n-r)!}$
$_{8}$C$_{2}$=$\frac{8!}{2!(8-2)!}$ -simplify like terms-
$_{8}$C$_{2}$=$\frac{8!}{2! (6!)}$ -write using factorial-
$_{8}$C$_{2}$=$\frac{8*7*6*5*4*3*2*1}{(2*1)(6*5*4*3*2*1)}$ -simplify-
$_{8}$C$_{2}$=28
