How do you work this out? 50th term is 349, 51st is 354, 52nd is 359. Find 1st term and 100th?

Question

if you could tell me steps to work out the question that would be great i have an exam coming up and i need an answer urgently,

Answer

Can I still answer??Or have you given up

How do you work this out?￼ 50th term is 349, 51st is 354, 52nd is 359. Find 1st term and 100th?