How does understanding place value you to subtract across zeros?

Which of the following represents the zeros of f(x) = 6x3 − 31x2 + 4x + 5? −5, one third , one half 5, − one third , one half 5, one third , − one half 5, one third , one half

On a piece of paper graph f(x)=5•(0.4)^x

In two or more complete sentences describe how to determine the appropriate model for the set of data, (1,1), (3,2), (6,3), (11,4).