Agirl out ? ? i'm confused as to solve this

F(n + 1) = f(n) – 8. if f(1) = 100, what is f(6)?

Quadrilateral efgh was dilated with the origin as the center of dilation to create quadrilateral e'f'g'h'. the quadrilateral was dilated using a scale factor of 2.5. the lengths of the sides of quadrilateral efgh are given. what is the length of side f'g'?

Hdtv screens usually have a width-to -height ratio of 16: 9. which screen dimensions are in the same proportion?