The sum of two unknown numbers is -40. The difference of those same two numbers is 25. What is the product of those two unknown numbers?

What is the inverse of the function f(x) = 2x + 1?

Assemble the proof by dragging tiles to the statements and reasons column

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?