An arithmetic sequence has these properties: a1 = 2
an = an-1 +5
What are the first four terms of the sequence?

i agree because i see the other persons thinking is clear

the answer is 9 because the question is telling how much it be together.

answers

\3. yes the presentation (i.e. odd numbers being written as differences of two squares) is possible for all odd natural number however the presentation may not be unique. for example,  57=112−82=292−28257=112−82=292−282.

\4. 2 can't be written as a difference of two squares because 4-1=3 and 1-1=0 and the difference of squares grows to integers larger that 3.

can i get some in proving questions 1 and 2?