Use thr factored form of a polynomial:
f(x) = a(x-p)(x-q)(x-r)(x-s)....
- a = a constant
- p, q, r, s, etc are the zeros
Degree of 4: means you need four factors
zero of 2, multiplicity 2: (x-2)(x-2) = (x-2)2
zero of 1, multiplicity 2: (x-1)(x-1) = (x-1)2
the graph of the function falls to the left and right: a = -1
f(x) = -(x-2)2(x-1)2