Help i will mark you as brain thing or whatever

What is the common difference in the following arithmetic sequence? 7,3,-1,-5

Which of the following is the shape of a cross section of the figure shown below

Alcoa was $10.02 a share yesterday. today it is at $9.75 a share. if you own 50 shares, did ou have capital gain or loss ? how much of a gain or loss did you have ? express the capital gain/loss as a percent of the original price