Need with math will star plz and explain

Can someone me with my hwplz(only the circled ones)

Algebra 1: unit 6 part 2 of test a) the table shows a linear function. x 0 1 2 3 5 13 21 29 37 45 53 (a) determine the difference of outputs of any two inputs that are 1 unit apart. show your work. (b) determine the difference of outputs of any two inputs that are 2 units apart. show your work.

One side of a rectangle is 7 feet shorter than seven times the other side. find the length of the shorter side if we also know that the perimeter of the rectangle is 306 feet.