Question

Can some one help me asap

Answer 1

It'd be easier to do #18 if y ou were to break it up:

                                                        14* (first term + 14th term)
Sum from n=1 to 14 of n =  S      = ---------------------------------
                                               14                       2
                                    
     14(1+14)
= ---------------- = 7(15) = 105 
           2

The sum of twice that is 210.  The sum of "1 from n=1 to n=14" is just 14.

The final sum is 210 + 14 = 224 (answer)