Please tell me if I got this one right or not

What are the coordinates of the midpoint of ab? ,1/2) /2,-1) ,-3/2) /2,-2)

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?

Evaluate each expression. determine if the final simplified form of the expression is positive or negative -42 (-4)2 42