Answer:
The graph goes through the critical points
a and b
The graph touches point b which mean that the binomial corresponding to this two point must have an even exponent. For point a, the graph crosses it which mean that the exponent for its binomial must be odd.
The graph also touches the origin wich means that one of the factors is x with an even exponent. The answer is
f(x) = x4(x – a)(x – b)
please add graph for next time!