Is this a function or not a function (2,5), (4, -2), (3,3), (5,4), (-2,5)

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?

Vanessa earns a base salary of $400.00 every week with an additional5% commission on everything she sells. vanessa sold $1650.00 worth of items last week.

Sum of the interior angles of a pentagon