2/3-1/12 the answer as a fraction

Click on the graphic until you find the right quotient. (36xa - 30xb) ÷ (-6x2)

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?

Is the point (0, 8) on the x-axis or y-axis? how do you know?