What is the domain of 3x^2-x-2

Erin bought christmas cards for $2 each to send to her family and friends. which variable is the dependent variable?

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

Plz , will award brainliest find an equation for the line that goes through the points (5,-8) and (13,4)