Solve.
3x = 9x^2– 10

Which ahows the graph of the solution set of 6x+4y< 12

How to do this , and can some one explain

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?