4th is 13 7th is 19 , that equals 6 difference, divide by two, 3 between each point. So now 3rd is 10, 2nd is 7, 1st is 4.
Now add the first 10, 4+7+10+13+16+19+22+25+28+31=175
Sets A and B are both functions because they all have different x values. Set C is not a function because it repeats the x value of 2 and gives it two different y values.
