Pls solve will give brainliest

Evaluate the expression for the given value of the variable 2×(c2-5) for c=4

Which representation has a constant of variation of -2.5

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.