What is the slope of graph

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.

Given that abcd is a rhombus, what is the value of x?

I’m really confused and need to learn this