Please help out with this question!

The late fee for library books is $2.00 plus 15¢ each day for a book that is late. if maria’s fee for a late book was $3.20, write and solve a linear equation to find how many days late the book was.

Franco wants to double the volume of the cone. what should he do?

For f(x)=2x+3 and g(x)=x^2- 8 find (f+g) (x)