Answer:
Is just a letter identifying the angle.
Since,Angles of a triangle sum up to 180 ,u add both the given numbers and subtract it from 180
All you have to do is combine 3x and 5x to = 8x. You can't combine 8x and 67y because they have different variables. so it's 8x+67y.
276 divides by 4 = 69
So 3x69 = 207 + 276 = $483
Yes, this is the right answer
Answer: 
Each term is half of the previous one, so the common ratio is 1/2. Then to get from the first term to the nth term, you have to take n - 1 steps, multiplying by 1/2 each time and by 6000 to account for the first term.
i hope this helps! :D