Question

A) 7C₂ =(Simplify your answer.)

Answer 1

This is a combination of the form:

`\begin{gathered} C(n,k)=nCk=(n!)/(k!(n-k)!) \\ where: \\ n>k \end{gathered}`

So:

`7C_2=(7!)/(2!(7-2)!)=(7!)/(2!\cdot5!)=(5040)/(2\cdot120)=(5040)/(240)=21`

Answer:

21