Question

Explicit formula for 20, 4, 4/5, 4/25, . . .

Answer 1

The explicit formula is An=A1*r^n-1

Your A(1) is the first term that would be 20, because 20 is the first term in your pattern

r is your common ratio which in this case would be 5, because you divide each number by 5.

Now you just plug those numbers in.

A(n)=20*5^n-1

Hope this helps ;)