i am working on this atm.
to solve you find the horizontal (x) intercepts.
so example graph A int is +3
then you find the equation where instead of f(x) etc, 0= the equation with the X value plugged in.
IE: 0=x^3-3x^2+x-3
would fit because when you simplify 0=0
0=3^3- 3(3^2)+3-3
0=27-27+3-3
0=0+0
0=0
it matches. so A would be the equation with f(x)
and continue in the same way