Piecewise function from given graph?

Question

it says to write a piecewise (compound) function for the graph to the right..

the graph has points at (0,0) (2,5) and (4,0)

Answer 1

we need more info about the graph. how are the points connected, straight or curved lines? we need a picture of it.

Answer 2

So, you have a straight line that connects (0, 0) and (2, 5), and then another that connects (2, 5) and (4, 0)?  OK.  If it's a piecewise function, then you are free to develop two different linear functions to represent each piece.  I'm going to presume that, at your level, you don't need me to show you how to get the equation of a line through two points.  So, your function will be

f(x) = (5/2)x for all x <= 2

= -(5/2)x + 10 for all x > 2

QED