The sum of the first four terms of an AP is 28 and sum of the first eight terms

The sum of the first four terms of an AP is 28 and sum of the first eight terms of the same AP is 88. Sum of first 16 terms of the AP is

2) If the roots of the equation (b - c)x2 + (c - a)x + (a-b) = 0 are equal, then

3) Common difference of sequence 5,8,11,14,… is

4) A.P whose nth term is 2n-1 is

5) 2,4,6,8,10,12,… is