# How do you use the binomial formula to find the coefficient of the z^19 q^2 term in the expansion of (z+2q)^21?

Jan 19, 2016

$210$

#### Explanation:

The coefficient will be the second term in the twenty-first row of Pascal's triangle (excluding the inside and outside ones).

This can be represented as ""_21C_2, or $21$ choose $2$.

Algebraically represented, this is

(21!)/((2!)(19!))=(21xx20)/2=210