Help pleaseee having little bit of trouble

Last one and the bottom answer choice is y=(x-4)^2+1 you guys!

The sum of the first eight terms of an arithmetic progression is 9m + 14. the fifth term of the06 progression is 2m - 6, where m is a constant.given that the first term of the progression is 26,find the value of the common difference, d and thevalue of m.

Which of the following constants can be added to x2 - 3x to form a perfect square trinomial?