Someone help me please. I need to quick!

What is the sum of the first 8 terms of the geometric series

The line plot below represents the number of letters written to overseas pen pals by the students at the waverly middle school.each x represents 10 students. how many students wrote more than 6 and fewer than 20 letters. a.250 b.240 c.230 d.220

What are the solutions of the equation x4 + 6x2 + 5 = 0? use u substitution to solve.