Find the approximate side length of a square game board with an area of 128 in2. HELP PLZ

The equation represents the function f, and the graph represents the function g. f(x)=3(5/2)^x determine the relationship between the growth factors of f and g. a. the growth factor of g is twice the growth factor of f. b. the growth factor of f is twice the growth factor of g. c. the growth factor of f is 2.5 times the growth factor of g. d. the growth factor of f is the same as the growth factor of g.

I’m really confused and need to learn this

How is this equation completed? i cannot find any examples in the book.