I need help with questions 17 and 18. Can’t figure it out.

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x

If 3 3/4 lb. of candy costs 20.25 how much would 1lb. of candy cost

The length of a rectangle is 2 inches more than twice it’s width. if the perimeter of the rectangle is 70 inches,find it’s length and width