Let's start by paying close attention to the terms of the given sequence.
cccc
a_1 & a_2 & a_3 & a_4
5 & 20 & 80 & 320
We can see that the ratio between any two consecutive terms is always 4. Therefore, we have a geometric sequence with a common ratio of 4. To find the next three terms, we will multiply the last term by 4 and repeat it two times.
rrrrr
a_5 & = & 320 (4) & = & 1280
a_6 & = & 1280 (4) & = & 5120
a_7 & = & 5120 (4) & = & 20 480
To graph the first seven terms, we will let the horizontal axis represent the position of the term within the sequence — this is the domain — and the vertical axis will represent the value of the terms — the range.
