A segment is only a "midsegment" if it connects midpoints. When labels above and below are 9 and 72, it is clearly not a midsegment. However, because it is parallel to the base, segments above and below on one side are proportional to those in similar positions on the other side.
72/9 = 56/(3x -20)
We can multiply by (3x -20)/8 to get
3x -20 = 7
3x = 27
x = 9
Let's say we're at the store and you want to buy 10 boxes of cookies for a party. Each box of cookies cost 4.89(counting tax), you don't know if you have enough money to buy the cookies with the $65.00 you have with you. You could round the price up to $5.00 and do more simple multiplication. Your total would estimate about $50.00. Now you know you have more than enough money to buy cookies. I hope that makes sense. :)
Assuming the sequence goes on like this 11,-33,99,-297,891,...,
its general formula is

So, the 9th term is
Choice a is the correct answer for the question