help? I'm a little confused, and also if possible, explain it so I can understand, if not that's okay

Kapil needed to buy a long wooden beam. he went to two sawmills that each charge an initial fee plus an additional fee for each meter of wood. the following equation gives the price (in dollars) of a wooden beam from the first sawmill as a function of its length (in meters). p = 5+20xp=5+20x

Which of these sequences is a geometric sequence a 1,2,4, 7, 11, 16, 22. b. 2.4.8.14.22.38 c.3.6.9. 15.18,21 d. 3,9,27,81,243,729,

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28