Can someone help me and explain it to me

Nick has box brads. he uses 4 brads for the first project. nick let’s b represent the original number of brads and finds that for the second project, the number of brads he uses is 8 more than half the difference of b and 4. write an expression to represent the number of brads he uses for the second project.

Find the roots of the polynomial function f(x) = x^3 + 2x^2 + x

Math i have no idea how to do a and b