Justify whether it is true to say that 
forms an AP as a2 - a1 = a3 - a2
False
Clearly, the difference of successive terms in not same, all though, a2 - a1 = a3 - a2 but a4 - a3 = a3 - a2 therefore it does not form an AP.
2
Justify whether it is true to say that forms an AP as a2 - a1 = a3 - a2
False
Clearly, the difference of successive terms in not same, all though, a2 - a1 = a3 - a2 but a4 - a3 = a3 - a2 therefore it does not form an AP.