Hi, are you able to answer question 6? can you show me how you did it also? good luck.
p. s this is on the topic of complex variables

If you solve it, then the answer would be 160+120i. you're supposed to do distributive property,but i did it differently. what I did was solve (6-2i)(6-2i). that equals 32-24i. there are 5 pairs of (6-2i), so you just add everything together. 32+32+32+32+32=160, and 24i+24i+24i+24i+24i=120i. giving you 160+120i. 
I hope this helped :)

20000 as first it increases by 2500 then by 5000 so next it will increase by 10000