What is the answer to this question? I need help.

Which expression is equivalent to7_/x^2 ÷ 5_/y^3? assume y# 0

Each person in an it department of 25 people works on at least one of 3 major projects: system security, program implementation, platform development. 10 people work on system security, 13 work on program implementation, and 12 work on platform development. 4 people work on system security and platform development, 5 people work on program implementation and platform development, and 2 people work on all three projects. how many people work on system security and program implementation?

Which shows the graph of the solution set of 3y – 2x > –18?