Does anyone know this ? it’s geometry and i have no clue how to do it !

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?

What is the approximate value of  x  in the equation below.–3.396–0.7080.3040.955

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)