+128475 W(x) is exponential, Z(x) is a polynomial
The point (0, 1) is on W(x) and the function grows as x increases....this is characteristic of an exponential growth function
For Z(x)....it is symmetric about x = 4.....so.....this is a probably a polynomial (a parabola )
[ It also might be an absolute value function but that isn't a choice.... ]
