Question 1047684
Note the description is Arithmetic Progression, and you are given first two terms, meaning these are the two CONSECUTIVE terms.   {{{7-3=4}}}, common difference.  General term of the sequence,  {{{3+(n-1)*4=highlight(3+4(n-1))}}}.


(a) and (b) should be very simple now.
(c) ? If you know how many terms in the sequence, call this v, then {{{(v/2)(firstTerm+lastTerm)}}}  is the sum of the finite sequence.