Question

Evaluate 7C3. 35 210 21 105

Answer 1

$\bf _nC_r=\cfrac{n!}{r!(n-r)!}\qquad \qquad \qquad \qquad \qquad _7C_3=\cfrac{7!}{3!(7-3)!} \\\\\\ \textit{use the }[!]\textit{ factorial button or the }[_nC_r]\textit{ button in your calculator}$