Assuming the small squares represent 0.5 unit, then there are zeroes at
x=-1, x=0 and x=2.
So the polynomial takes the form
y=a(x-(-1)(x-0)(x-2)
or
y=ax(x+1)(x-2)
Since the graph increases indefinitely as x-> + ∞, a is positive, therefore
y=ax(x+1)(x-2) where a>0